Best config for 2 adults 5 kids in rented minivan (Chevy Uplander)?

[moismom]

Ok my sister and I are looking at visiting my parents at the same time and splitting a rental van. It looks like the most common rental minivan is a chevy uplander. We have 5 kids between us. My 6 yo will be travelling with the little cheap booster (she's over 4 feet tall and very mature in the car so this is fine. The littlest baby will be in a graco snugride. The other 3 kids are in marathons right now. Is there any way to make this work? Which combo would work best. My other option is to put my baby in an Eddie Bauer infant seat - but I hate this seat - (a friend gave it to us - it's one of those that adjusts from the back). That would give us one backless booster, 2 marathons, a snugride and an Eddie bauer infant seat. Alternatively I could put my then just 4yo in my oldest kid's parkway booster - however she's just 31 pounds and 38" now so I'm not sure how comfortable I am with that. Suggestions would be greatly appreciated. Another reason I hate to take the Eddie Bauer is that it's such a pain to get in tight while the marathon while huge is so easy. Please help.
Thanks,
Kinsey

[daniele_ut]

I'm not much help in the carseat configuration puzzle, but I wanted to throw out another option. Last time we took a vacation with the in laws we found that it was actually cheaper to rent 2 midsize cars than it was to rent one minivan for the same time period. We actually found that to be more convenient because we could split up if we wanted to.

[moismom]

Ok...in that case is there a smaller car that I can fit my 6yo's backless booster and 2 marathons or atleast the booster, a marathon and an infant car seat?
Thanks,
Kinsey