Hi
My two boys are now 4 and 5, so hopefully I can help you out!
Car seats - I'd recommend you take your own, although yes they are bulky and having them means more stuff the airline can lose!!
But the ones from the car hire company leave a lot to be desired - as said before the have no instructions and noone bothers to help you fit them. They are grubby and not very fresh

. We had the pleasure of renting one a few years back when we had a problem with our own one and I wouldn't do it again. Our two are using booster seats now, and they are not too bad for carrying can even sit on them in the aircraft.
Strollers - you didn't mention how old your other child is? Your 4 year old is the elder? My two sons are very close in age, when we went in 2000 we had 2 of our own buggies with us, one son was 1 year old the other was almost 2 and this seemed to work ok for us. The wee one was too young to put into a disney stroller, and I wasn't keen on taking our twin/ tandem buggy - (they sat one behind the other...) becasue it was so heavy and awkward. Our trips in 2002 and 2003 have both used the double park strollers, and I do like them, despite the $15 per day I think they are worth it - easy to push and the kids love them, the can climb in and out really easy. We have also taken our own single strollers for days out at DTD, Belz ets - it was so hot they were happy to be pushed about!!! Last year we only took one stroller - for DS age 4 who has a slight disability and DS age 5 was really tired even just looking around some shops, so we bought a $10 one from
WalMart. It really wasn;t up to much, but it did the trick for the 2 weeks we needed it. He is a very small 5 year old and it was still quite hard to move around - hurted the palms of my hands trying to push it!!! The front wheels didn't move..!!
Our next trip is 2005, and I still intend to hire a double stroller for them then too - even though they will be 5 1/2 and 6 1/2.

but I wouldn't expect them to use it all the time - only when they need a rest, and it can be handy for carrying things when they aren't in it!!!
Hope this helps
Cath
