You can do only 8 phyical and 8 crafting leves. You can do all 8 in one town or split them up between the 3 towns, doesn't matter at all. Just keep in mind, those are the only 8+8 you can do until the Leve reset.
If you don't mind the running, I've found it best to hit all 3 cities. I look for leves that have gear rewards in them. Free gear at these levels is a really nice deal, and usually the gear is close to the rank you are.
Hope that helps.
Pack your own lunch and bring nothing but Pixie Stix and Pop Rocks and get your liberty on.