In Georgetown, there's the MountainBuzz Cafe and the Alpine Inn just off the interstate, the Happy Cooker farther into town, and for ice cream and souveniers, visit the End Of The Line about a two-minute walk from the Happy Cooker.
There's also a Subway just past the HGI Visitor's Center *cough* if you're looking for something quick.
There are other places to eat; these are the one's I've visited. Sorry that I don't have better directions.
I don't know of any eateries in Silver Plume - outside of the Loop Gift Shop, of course! *S*
-Jim