Here in WI, we don't have anything that compares to Johnson Creek, but there are a few good places to camp:
1) Three Lakes (40D): Nicest grass runway I've ever landed on (and lit, too), camping on the field, a dirty but usable bathroom in the small building onsite, and a camp store, restaurant, and boat rental facility on the shore of the lake across the street from the north end of the runway.
2) Tomahawk (KTKV) and Adams-Friendship (63C): Both have 24-hour accessible bathroom/shower buildings, camping allowed on the field, and fire pits. Both are paved-runway uncontrolled municipal airports. KTKV has an "airport attendant" who lives in the house on the field, 63C's manager lives right across the street and will lend you his own car if you need it. Super-nice guy (obviously).
As far as neat backcountry places I've been that aren't in Idaho, I'd have to say that Gravelly Valley, CA was pretty cool - Had to chase a pair of Elk off the runway before landing!