We have a BIG 5 1/2 year old (48", 68 lbs) son who does not have the stamina to walk all day at the parks, and have read on these boards that the double strollers are "roomy" - he would be sharing it with his much smaller 3 year old brother. Do you think he'd fit in it for a quick rest now and then? (we're not really worried about comfortable here, just to be able to get him off his feet). Do they rent wagons at the parks? Our 3 year old son also needs to ride along. Any suggestions/comments are appreciated. Thanks for your help, this board is great!