I live in Lower Macungie near where they are building the new elementary school and I work near the west end of Allentown. My commute is at most 15 minutes (even during rush hour) and I can get there four different ways that all take close to the same amount of time give or take 2-3 minutes.
The schools are good in East Penn and you can get good sized single family homes and town homes (new construction or resale) for a decent price. In this buyers market lots of houses have been on the market for a while. You could probably get a good deal. Good luck!
I haven't been to Bath or Nazareth in a while. They seem more like suburbs of Bethlehem and Easton to me.