depending on State, some allow rest stops to be used overnight - check the local regs. many walmarts, cracker barrels and bass stores allow overnights.
an app such as RVPARKY ( which is free for iphone) will help you find a place whether a parking lot, rest stop or rv park.
koas are always a pretty good standard, but usually more costly- great for the weekly laundry stop though.
koa offers a membership/discount- we have yet to break even on one of these
you need some reading:
http://roadtreking.com/
http://roadtreking.com/apps-websites...ndocking-spot/
Campskunk suggests:
http://www.overnightrvparking.com/ a membership site
more on him- he has great suggestions:
http://roadtreking.com/fulltime-rvin...pskunks-story/
Mike