The DS walk from the bus stop to Raglan Road is less than 1/3 mile...definitely nowhere near the length and time quote you saw - so no worries there. When you get off the bus, enter DS through the tunnel, go straight ahead towards the Guest Welcome Center, then towards the right past Frontera Cocina, hang a left and cross the bridge - you'll see Raglan on the right. Very easy walk.
Walk or take the monorail to Contemporary - that will be your shortest way out of MK...hop the Disney Springs bus from there. You could also take the monorail to any of the MK resorts and head to their bus. It's probably a close call between walking to the Contemporary bus stop vs walking down from the monorail and out the building to the bus stop, so you don't really save much walking distance taking the monorail. If you took the boat to Wilderness Lodge from MK, then walked to their bus stop, it might actually be slightly less overall walking than Contemporary, but the slow boat ride might take a little longer.