Trumansburg is nice, you can go up the west shore of Cayuga or over to Seneca Lake. Traffic is lower than Ithaca proper.
Newfield is kind of tough. You can ride into Ithaca, which would mean significant hills going back. Or you ride south toward Danby, Candor, or Elmira, which is nice riding but no lakes, and most of the roads are 55 mph rat races.
The only real plus of Newfield, IMO, is Robert H. Treman State Park, which is an absolute gem to hike. Trails were built as part of the post-depression labor pool, and they are amazing.
Of all your choices, the Best Western in East Hill Plaza is a very nice choice. You can go all directions from there, and it is close to Cornell Plantations, which is another one slick outdoor area in Ithaca. Of course, I spent the night of my wedding in that Best Western, so marital bliss depends on me talking it up.
