As long as you're still partially mobile (i.e. can walk a few feet and cope with onr or two steps to get in and out of ride cars) you shouldn't really have any problems. As you may have guessed, Swiss Family Robinson Treehouse is out, and you won't be able to do much on Tom Sawyer's Island (basically you can ride there and back on the raft if water levels are right), but other than that, most things are fine. Most of the rides with moving walkways can be slowed or stopped if you need more time to board (Peter Pan is the exception to this).
Here are a few websites that might help you. Most if not all of these are linked to in the
disABILITIES FAQ:
All Ears' photo gallery of ride cars. This should give you an idea of what the transfer will be like
The Mouse on Wheels. Detailed information on transfers to rides.
Tips for wheeling Disney. This is a useful thread that collects a lot of our tips on how to do Disney on wheels.
You might want to consider renting a wheelchair or
ECV for the length of your stay, from an offsite rental company. Details of a number of such companies are available in the FAQ. If you rent of site it is likely that your chair / ECV is lighter, more maneuverable, available for use 24/7 (so you can use it to and from the buses, around your resort and at DTD), and often length of stay rentals end up cheaper then renting each day at the park. If you do rent off site, make sure you read the FAQ section on Disney transport.
Good luck and have a great trip!
