Traveling through tomorrow, are we able to "camp" overnight like at walmarts to get rest?

Yes

Not likely-- I have not seen it there, and it is mostly rural (mountains). On Route 81 where it intersects with Rts. 11 &15 You may have some luck in and around Sellingsgrove and Lewisburg. North and south of Harrisburg. There are lots of actual camp grounds in the area.

Thanks for the info