Buena Vista Palace is sort of behind and across the street from the Marketplace end of Downtown Disney (I think that the entrance to the hotel is across from a guest entrance/exit to Disney's Saratoga Springs resort that's across the lagoon from DTD).
The Regal Sun Resort is the first hotel on Hotel Plaza Boulevard just a short distance, and across the street, from the walk-in entrance to the DTD Marketplace section.
The Lake Buena Vista Resort (I think it's a Best Western) is on the same side of Hotel Plaza Boulevard as Regal Sun, perhaps a third to a half of a mile further away.
On the opposite side of Hotel Plaza Boulevard are:
The Hilton Orlando Resort. Pretty close to DTD but across the busy Hotel Plaza Boulevard/Buena Vista Drive.
The new Holiday Inn is next on that side of HPB - about a quarter mile beyond the Hilton.
The Royal Plaza Resort is right next door to (and about a tenth of a mile from) the Holiday Inn.
And the last of the Hotel Plaza Boulevard hotels is a Doubletree that's about a quarter mile beyond the Royal Plaza.
Any of these hotels is easily walkable to Downtown Disney, you'd do much more walking inside the DTD complex than you would getting to it from any of them. There are sidewalks and crosswalks from the hotels to DTD and the walk is well lit.
I'd think that any of the online travel agencies, like hotels.com, travelocity, orbitz, expedia, etc., would be able to show all of these hotels and give you an idea of pricing relative to one another.
And I agree with you that for one night spending an extra $20 for the "Disney View" wouldn't really be worth the money - though you'd probably be able to see nightly fireworks off in the distance.
Dick Taylor