Let me start off with two things.. First, at this point I am very happy with the C, how well it fits one rear facing car seat and don't expect to need another one anytime soon. Second, please don't start recommending the regular liftback or the V or another larger car... I was wondering if anyone had personal experience with more than one car seat (one rear facing) in the C. Any chance of fitting a passenger in the back? Were you able to reasonably manage on trips with two kids? I realize that the average family shops for a minivan or suv when thinking about two kids. I also realize that the C is no smaller than the average family car in Europe..
I'll give it a shot. We have 2 (4yo and 2yo). Depending on carseat, we have Britax Marathon (on the smaller side of carseats) and can fit rear facing but it will contact the front seat and/or give the passenger less leg room. The Recaro booster fits in just about any car. With this setup there will be no room for any normal size adult it safely buckle up. All thats left is about 10" of middle seat space for misc items. YMMV but if you pack light enough, do not need a giant stroller, plus limit items purchased from trips it is definitely doable. I often go to Costco with the C, the hatch area will fill quickly and often utilize the cabin for some small items. hope this helps
My mom and two of my nephews were visiting me this summer. We had couple of road trips with my wife seating in the front seat and my mom, my 12 and my 3 years old nephews seating in the back. Was a little bit tight but my passengers did not complain.
I have a five year old and two year old. Both my wife and I have Prii C and often have to swap car seats. The five year old sits on a booster seat but the two year old still uses a complete car seat (with the back). Changing the car seats between her car and mine is a pain in the butt. The latches are really hard to hook into but you have to dig around for them. But traveling with the two kids and my wife is fine and roomy, no complaints.
Here are 2 random car seats in the C for our 5 and 3 year olds: It's not really possible to sit a third person back there with the car seats. A small person can squeeze in, but it's a quite a chore to locate the seat belt buckle.
Keep in mind that there isn't much room for a third person in the backseat even without any carseats.