My oldest child uses a booster (Maxi-Cosi Rodifix), my middle child uses a carseat (Maxi-Cosi Priori) and once my third child is born he will be in an infant carrier (Maxi-Cosi Mico). I drive a 2011 Honda Pilot and it does fit all three carseats on one row. From experience, what ways would you recommend to place their seats? My first choice was to put my oldest in the middle. She can buckle her seat belt by herself and it would be easier to attach and detatch the infant seat from the side seat. I would buckle my toddler from the other side as well. Or should I use the third row and send my oldest all the way to the back (I never use that third row)? How safe is it to have a booster on the middle seat? All ideas welcome!
Because there should not be any major safety factors determining seat location (all 3 positions should be as safe as each other unless you have specific ISO-FIX fitting requirements) I think you are taking the right approach and looking at lifting, buckling and other physical constraints. Always have your youngest close to the door, as baby carriers are heavy and awkward to buckle.
Then pop your eldest in the middle - if they can buckle themselves then that makes life easier. With us, they had to be buckled in first though, as the middle child's seat obstructed the belt points. The main thing is to find out what works for you though and go with that.
In fact, I have the same configuration.
Put the older two kids in the third row, on the sides, leaving the central area clear. This would benefit you when you put your older kid on the booster and put the car's seat belt into the buckle.
Benefit: You do not have stick your hands between cars seats to find seat belt's buckle for your oldest kid.
Not so benefit: This would take some bending your back when buckling/unbuckling your older ones, but they will have more room for their stuff. You can also take advantage of the free floor area.
Put the youngest one in the second row. Now based on your most typical travel plans, do one of these:
I've heard carseat techs say you should put the least protected seat in the most protected position. Typically this means you want the booster seat in the middle, and the infant seat and harnessed carseat on the sides.
From a practical sense, buckling a booster seat in the middle between two carseats can be challenging in some vehicles, and putting some carseat(s) in the backseat may be easier.