Hello Sabrina!
Disney transportation can sometimes get a bad wrap, but in all the times I have visited the parks I really haven't had more than a minor inconvenience and it's usually only because there are lots of tired Guests wanting to go to the same place as myself. It's hard to tell which resort has the shortest bus ride because it really depends on which park you are headed to, but I can definitely offer you some suggestions based on my past experience with Walt Disney World Resort transportation.
Deluxe Resorts: With the Deluxe Resorts I usually like to stay closest to Magic Kingdom Park at a monorail resort (Disney's Contemporary Resort, Disney's Polynesian Village Resort or Disney's Grand Floridian Resort & Spa) or at Disney's Wilderness Resort which offers convenient water taxi service to Magic Kingdom Park. For an adult trip we love to stay at one of the resorts near
Disney's BoardWalk due to the fact that you can walk right into Epcot.
Moderate Resorts: Disney's Port Orleans Resorts are nice because they also offer water taxi service to the Downtown Disney Area, but I prefer Coronado Springs Resort. The resort is large, but you can request a room near the bus stop which drops off and picks up first, making transportation extra easy.
Value Resorts: With the Value Resorts I prefer to stay at Disney's Pop Century Resort or Disney's Art of Animation Resort as they don't normally share a bus with other resorts.
I hope this information helps, Sabrina, but if there is anything else I am able to assist you with, please let me know. Have a wonderful time planning your vacation!
Magical Wishes,
Lauren