So sorry about the car accident, but a trip to WDW may be just what the doctor ordered.
I recommend calling Disney reservations (if booked thru Disney) at (407) 939-5277 and tell them that you were recently injured in an accident and would appreciate a room close to the main elevators. If you booked through a TA, then contact them. The corridors can be very long and a bit of a walk from the elevators. At the YC, you are 99.9% assured of getting a room with a full balcony, so that you can sit out and relax, whenever you want, without needing to leave your room.
If you are all completely mobile, then the higher beds at the YC should not be an issue (bed height is about 6" higher than normal). However, the accessible rooms have standard height beds, if you think there would be an issue. That is also something that can be addressed on the phone. I suggest letting the CM know that you are celebrating your daughter's 16th birthday.
The outdoor pathways at the YC are very easy and straight forward. SAB (the pool complex) is right in back of the resort building. The boat dock is about a five minute walk out the main back door, for transportation to the Boardwalk, Epcot, Hollywood Studios, etc., and you can walk to Epcot in about 10 minutes.
Your MagicBands are linked to your accounts, so, as long as
MDE lists your YC reservation, there is no problem. If there is an issue, the front desk at the YC can take care of it for you.
Enjoy your trip! The YC is a wonderful resort.