Good points, Texas Line. I had thought of the Cays as cheaper too, but the one-story homes there are not the size he is looking for. And IIRC, no stores/businesses are “walkable” from there.
Earlier in this thread I mentioned to him the eastern foothills of Mt. Helix in La Mesa (for one-story SFR sizes). However, there may be a few larger one-story homes in the vicinity of Lemon Ave. Elem. which is certainly near the “walkable” portion of La Mesa Village. As for market availability, I haven’t checked into this.
I too, feel the OP may need to make a slight size compromise to remain close enough to work to avoid daily commuting hassles to/from 92021, perhaps down to 3000 – 3500 sf.