Santa Fe is not a very big city, and the Plaza area and Railroad District are quite walkable. We found a beautiful little adobe house just a few blocks south of the plaza district that gave us easy walking access to both areas, plus we could even walk to Museum Hill. For us, it was the perfect location.
If you aren’t as lucky as us, I’d recommend looking at the Railroad District, or maybe a little north of the plaza. North the terrain gets hilly, so you’ll have to climb a bit to get home, but the views would be great, and we did notice that there are more apartments available there. It would be cheaper to stay down Cerrillos Road, but the area loses it’s unique charm there and starts to become every other American suburb.