When my mother visited me, she stayed in the Rock 'n Roll section. The walk to the bus stop wasn't far at all. Granted, it's not just outside the door, but it's not really that far.
As for Bus Transportation... the All-Stars generally receive the most frequent busses, as well as the most amount of busses. The reason being... It's got the most amount of guests.
During the morning... yes... the busses will be a bit crowded. However, we run MOD in the mornings... (Magic On Demand) Busses are staged between All Star Sports and Music, and are dispatched on a demand basis. In addition, incoming busses to DAK are dispatched to the All Stars going back to thier home territory.
During the afternoon hours, busses run frequently, and aside from Parade Exits, and rain storms, pretty much should run just fine, and not be crowded at all.
At park closing, we go back to floating mode, and busses are dispatched to the load zones by demand. All Stars will often "Double-Load"... It will be crowded, yes, but the busses come very frequently.
It always amazes me that people are shocked that the busses are crowded in the mornings and nights... Y'all aren't the only ones wanting to travel.
For Animal Kingdom, Epcot (Daytime) Disney/MGM Studios, and Downtown Disney, the busses service all three All-Stars. For Magic Kingdom (all day), and for Epcot (at park exit), the busses are separated. Some busses run Sports, Music, Movies... Others run Movies, Music, Sports.
Also, one thing to note... At Sports and Music... the Disney/MGM Studios and Downtown Disney share a load zone. At all three resorts, Epcot and Blizzard Beach share a load zone. Please make sure to read the Destination Sign on the bus to see which location it services. If the Bus says "BLIZZARD BEACH" it goes to Blizzard Beach NOT Epcot. (I know that sounds simple, but every single time I pull in... someone asks me if I go to Epcot)
(Note that in the past, there was a dedicated Blizzard Beach bus, as well as the Epcot bus would service Blizzard Beach. This is no longer the case.)
One more note... Even though the All-Stars are "waay out there" the bus rides are not long. Magic Kingdom is typically a 13 minute bus ride. Epcot is 10 minutes. Studios is 10 minutes. Animal Kingdom is 6 minutes. Downtown Disney would be the longest at 17 minutes (due to traffic...)