Fairfield Inn is maybe 1/2 mile north of downtown near Pioneer Park but not a lot nearby the hotel itself. It is walkable to downtown but it's not in the middle of anything.

TownPlace Suites is on the southwest side of town about 1/2-3/4 mile from the Old Mill District. There are a few restaurants nearby (Cascade Lakes brewpub is across the street, Pacific Pizza & Brew is maybe 1/4 mile, and the Original Pancake House is across the parking lot if you want a really big breakfast). Riverbend Park and the River trail are nearby.

I live in Bend so haven't stayed in either. I would pick the TownPlace based on the surrounding area: lots of trees, near trails, on the way to the mountain, etc. Fairfield would be a better pick if you want to hit all of the downtown brewpubs and walk back -- Townplace is much farther from downtown.