Night drive

The first idea that comes to my mind is driving at night. Our son often falls asleep in the car, most likely because of the movements and the white noise.

Prepare and pack the car during the day or early evening. Make sure you're well rested on this day. Do a shorter version of your bedtime routine, and do it earlier than usual, then get in the car and start driving. He'll fall asleep soon enough.

Both parents can take turns driving and sleeping, and you could also plan a short (<20 minutes) power nap around midnight to keep fresh, possibly with some booster music. The important thing is to take a break before you get really tired.

Drawbacks?

Most obvious is that you'll both be kind of tired the following day.
-Solution: Since you're visiting your family, perhaps they can lend a hand with attending to your son.

You might also be tired during the drive, as I've already stated.
-Solution: Start out well rested. Take breaks early. Consume enough fluids and proper(!) food to keep you going.
-Booster music: That booster music is something I actually use, and despite appearances it really, honestly works! It works best if you're familiar with it in advance, so some "training" (conditioning, really) helps. Must be used with headphones, and in-ear headphones are better than old-school ("walkman") on-ear headphones.

It's also worth noting that some people are more comfortable driving in daylight, for various reasons. I personally prefer the night, as long as the roads are in decent condition and I know my way around (I wouldn't like to weave through unfamiliar, worn and narrow Italian streets at night).
-Solution: Choose an easy route even if it's a small detour. Know the way, and/or use a navigation system that you know you can trust.

_{Note: The pzizz link is an affiliate link. I forgot what it earns me but it's probably not a lot, and doesn't cost the buyer anything. I believe in the software, and there's a $10 "energizer pack" available as MP3. The more expensive choices offer more, but that's irrelevant to the question.}

Night drive

The first idea that comes to my mind is driving at night. Our son often falls asleep in the car, most likely because of the movements and the white noise. I have a 14-hour drive to my family, from Austria to Denmark, and this is how I would do it.

Prepare and pack the car during the day or early evening. Make sure you're well rested on this day. Do a shorter version of your bedtime routine, and do it earlier than usual, then get in the car and start driving. He'll fall asleep soon enough.

Both parents can take turns driving and sleeping, and you could also plan a short (<20 minutes) power nap around midnight to keep fresh, possibly with some booster music (see below). The important thing is to take a break before you get really tired.

Drawbacks?

Most obvious is that you'll both be kind of tired the following day.
-Solution: Since you're visiting your family, perhaps they can lend a hand with attending to your son.

You might also be tired during the drive, as I've already stated.
-Solution: Start out well rested. Take breaks early. Consume enough fluids and proper(!) food to keep you going. Make sure that the driver can safely access some snacks and fluids even while the co-pilot is sleeping.

It's also worth noting that some people are more comfortable driving in daylight, for various medical and psychological reasons. I personally prefer the night, as long as the roads are in decent condition and I know my way around (I wouldn't like to weave through unfamiliar, worn and narrow Italian streets at night).
-Solution: Choose an easy route even if it's a small detour. Know the way, and/or use a navigation system that you know you can trust.

When you return to your home, there's no family to assist you.
-Solution: Make sure you have at least one day at home before you need to get back to work. Yes, that will shorten your stay, but it will reduce the impact at home.

Booster music:
That booster music is something I actually use, and despite appearances it really, honestly works! It works best if you're familiar with it in advance, so some "training" (conditioning, really) helps. Must be used with headphones, and in-ear headphones are better than old-school ("walkman") on-ear headphones.

Anecdote:
The last time I drove 14 hours, we started in the morning and arrived in the night. Our son was an infant then, and slept the whole time except for feeding and changing. We were very surprised that he slept through the night anyway! I'm sure I won't be that lucky with a toddler though :-/

_{Note: The pzizz link is an affiliate link. I forgot what it earns me but it's probably not a lot, and doesn't cost the buyer anything. I believe in the software, and there's a $10 "energizer pack" available as MP3. The more expensive choices offer more, but that's irrelevant to the question.}

Night drive

The first idea that comes to my mind is driving at night. Our son often falls asleep in the car, most likely because of the movements and the white noise.

Prepare and pack the car during the day or early evening. Make sure you're well rested on this day. Do a shorter version of your bedtime routine, and do it earlier than usual, then get in the car and start driving. He'll fall asleep soon enough.

Both parents can take turns driving and sleeping, and you could also plan a short (<20 minutes) power nap around midnight to keep fresh, possibly with some booster music. The important thing is to take a break before you get really tired.

Drawbacks?

Most obvious is that you'll both be kind of tired the following day.
-Solution: Since you're visiting your family, perhaps they can lend a hand with attending to your son.

You might also be tired during the drive, as I've already stated.
-Solution: Start out well rested. Consume enough fluids and proper(!) food to keep you going. Take breaks early.
-Booster music: That booster music is something I actually use, and despite appearances it really, honestly works! It works best if you're familiar with it in advance, so some "training" (conditioning, really) helps. Must be used with headphones, and in-ear headphones are better than old-school ("walkman") on-ear headphones.

It's also worth noting that some people are more comfortable driving in daylight, for various reasons. I personally prefer the night, as long as the roads are in decent condition and I know my way around (I wouldn't like to weave through unfamiliar, worn and narrow Italian streets at night).
-Solution: Choose an easy route even if it's a small detour. Know the way, and/or use a navigation system that you know you can trust.

Night drive

The first idea that comes to my mind is driving at night. Our son often falls asleep in the car, most likely because of the movements and the white noise.

Prepare and pack the car during the day or early evening. Make sure you're well rested on this day. Do a shorter version of your bedtime routine, and do it earlier than usual, then get in the car and start driving. He'll fall asleep soon enough.

Both parents can take turns driving and sleeping, and you could also plan a short (<20 minutes) power nap around midnight to keep fresh, possibly with some booster music. The important thing is to take a break before you get really tired.

Drawbacks?

Most obvious is that you'll both be kind of tired the following day.
-Solution: Since you're visiting your family, perhaps they can lend a hand with attending to your son.

You might also be tired during the drive, as I've already stated.
-Solution: Start out well rested. Take breaks early. Consume enough fluids and proper(!) food to keep you going.
-Booster music: That booster music is something I actually use, and despite appearances it really, honestly works! It works best if you're familiar with it in advance, so some "training" (conditioning, really) helps. Must be used with headphones, and in-ear headphones are better than old-school ("walkman") on-ear headphones.

It's also worth noting that some people are more comfortable driving in daylight, for various reasons. I personally prefer the night, as long as the roads are in decent condition and I know my way around (I wouldn't like to weave through unfamiliar, worn and narrow Italian streets at night).
-Solution: Choose an easy route even if it's a small detour. Know the way, and/or use a navigation system that you know you can trust.

_{Note: The pzizz link is an affiliate link. I forgot what it earns me but it's probably not a lot, and doesn't cost the buyer anything. I believe in the software, and there's a $10 "energizer pack" available as MP3. The more expensive choices offer more, but that's irrelevant to the question.}