Hello fostrmom2mny...
I have stayed in a Vacation rental home the past two times we were in Florida and LOVED it.!!! Although I love staying on site and have actually spit the vacation up between on site and Vacation Homes we thouroughly enjoy having our own home.
We have used two different companies but to be quite honest with you I think they are all really one company with a bunch of names

. Nevertheless we were quite pleased and for a larger family they are a must. Although yes you will need a vehicle to get around but once you get to know the Kississime area it really isn't that hard. Believe me when I say everyone will appreciate having their own room, snacks in the fridge, not falling over each other when getting ready in the A.M. and your own pool to yourself.
The last time we went, which was last March the reservation company made a mistake. We had put in for a 2 bedroom house for DW, myself, DD and Nephew. Well apparently they were out so they gave us a five bedroom house, 4 bathrooms, 2 car garage...etc for the same price, not bad for $99 a day.
Anyway I would definately reccommend them, but just the same as anything be careful, but I think most on the Net are reputable. We used
Homes4UU but like I said I thnk there isn't much difference between them all.
If you want to know anything else feel free to e-mail me and I will try to answer your questions.
Have a Disney Day...