Tahoe is moderately cheap. You can rent a house for a month or two at a reasonable cost if you shop around a bit. Every year there are a couple of groups of college kids from California doing their summer at altitude up there.
Trail elevations range from 7000 feet to 12000 feet. There are lots of choices for hilly runs and a few choices for moderately flat runs. Almost no choice of asphalt running, pretty much all dirt or decomposed granite trails.
Multiple grocery stores in town, some good bars, obviously the lake is fantastic, and it is all not too crowded in the summer, since the main tourist season is winter. Also no meth problem like there is in Flagstaff.
To drop out of elevation a little for track work, Reno isn't too far or Sacramento is a little farther if you want to get all the way down from elevation.
Truckee is similar but usually a little cheaper and the bars will be a little divier and the lake is a little warmer and not as clear. Still nice though.
Oh and incredible stream fishing all around both towns.