I hope that you already have hotel reservations. If you don't, they may be hard to get on-site, try some hotels in the Kissimmee area.
If you don't have dining reservations already, you probably won't be able to get those, either - plan on eating counter service. Also, as a previous poster mentioned if you can get a room at Saratoga Springs you will have a kitchen (in a 1 or 2-bedroom) so you could prepare some food in your room.
As for the crowd, I think it all depends on your expectations. If you are expecting to go on every ride, you may be pretty stressed out and exhausted after your trip. While I'm sure it can be done with some creative planning, use of fast passes, and maximizing your time in the park, it's not going to be relaxing.
I think if you go expecting to hit some of the rides that you really want to do (use fast passes, get them right away as they get "used up" for the day pretty early during busy season), but also with the understanding that you just can't do it all in one trip, and enjoy the atmosphere, parades, shops, etc., then it can still be a very enjoyable time. Just remember that Disney is not always going to be as crowded as you'll see it that week, I'd hate for you to never want to go back because of the crowds!!
If it's your only chance to go, I say go for it, but just be sure that you have reasonable expectations for what you're going to be able to do.