I've just been reading about how much walking there is to do - is there anything in the parks to hire to get around them easier? Like scooters or buggies or bikes? If so, what sort of prices are they and are they annoying for other walking guests? Or are there buggy lanes?
You can rent strollers and scooters from Disney at the entrance of every park.
There are also rental services in Orlando (Walker Rentals comes to mind, because I see a lot of people with scooters from there)...if you rent from them, I believe they will deliver the unit to your resort if you are staying on Disney Property.
They do annoy some walking guests on busier days, but it's not a function of the unit itself, it's who is driving it and how much attention they are paying to their surroundings.
I've ran into people who are courteous with their strollers / scooters, and I've run into people who are not. The former are not an issue. The latter...well, what else can you do but shrug it off and keep going with your day?
There are no designated lanes in the parks for strollers or scooters, however there are designated "parking" spots where they can be left while you ride a ride or explore areas where strollers / scooters won't work.
People with scooters / wheelchairs are given priority seating on the busses, however each bus has a limit on how many scooters it can handle (2, as I recall), so be aware that just because you have a scooter, it doesn't mean that you will always be allowed to board a bus. It's rare that it fills up, but it does happen.
Strollers taken on the busses must be able to be folded down.
Private Segways are not allowed on the parks, and Segway tours have been discontinued.