Not sure about film development but printing digital photos should cost around 0.20c per print. It works out cheaper to get more than 50 printed at a time. Look for coupons in local papers for places like Walgreens, WalMart etc. It's great to sit on the plane on the way home and look over your photos.
It costs around $12 to get 100 digital prints to CD in WDW. Its much less than this off site. The old Eckerd (Now CVS Pharmacy) were always good, as are Walmart, Walgreens and some of the larger Publix stores.
You can no longer get film developed at Disney, so you would have to go off-site for that. But you can get your digital pictures downloaded to CD at the camera centres in the parks and, in the near future, at the resorts as well.
It is easy to get the developed at those places. As to distances, depending on which part of WDW you are at there should be one within a 5 mile radius. Will you have a car? If so I'll look for some directions to the closest WalMart / Walgreens for you.
I've never gone offsite with no car before so I think I will have to let someone else answer this for you as I've no experience of using public transport in Orlando - I am sorry!
It might be worth starting a separate thread called something like "Best way to get to Walmart or Walgreens with no car"
I have never had a problem on past trips, though my last visit was 18 months ago. I just drop my film off at the resort shop and collect my prints the next day. Have they stopped offering this service?
I like to get prints as I finish each film so I can see what I have taken. I never rent a car, so getting offsite would be a problem.
Andrew I'm pretty sure they did not offer this in December 04 when we were last there - it was digital only, transferred onto disk.
The first two times we did it we had to return the next day to get the disk - but they swapped over to a new system while we were there and did it "while - u - wait". We were one of the first people to have this done at Epcot according to the CM.