I just looked in my book (851 pages) of
The Wright Guide to Free & Low-cost Campgrounds (2015) in that area, and don't see a single place. This book only lists places that cost $12 or less.
Walmart will sometimes close off their parking lot to camping if they are storing stuff in the parking lot (like the spring garden stuff), or have some kind of repairs to do (like septic work).
At https//FreeCampsites.net it shows Tulalip Resort Casino 18 miles W of Monroe. There are a few others, but they tend to be over an hour of drive time from the towns you listed, out in the boonies.
Would you consider housesitting? Here's a website with a directory of all the major housesitting websites:
http://ultimatehousesittingguide.co...-overview-of-all-major-housesitting-websites/ There seems to be a charge of $25 to $100 to join, but I've heard the minimum fee the housesitters seem to charge is $10 a day. Some people who charge $10/day will include a pet for that, and they multiple it by the number of extra pets (i.e., 3 dogs = $30/day). OTOH, just starting out, $10/ for 2 wks would be $140 that you didn't have before, and you'll be living in a more secure situation. I don't know how it all works, but it might be something to look into. The living arrangement could vary considerably -- they might let you live in their yard in your rig, or they might prefer you stayed in the house so it looks more lived-in (lights going on and off, etc), with access to shower, kitchen, and laundry.
If you take a quick look at this site, it show how much it costs for the family to BOARD a pet at a facility, and
everything costs more than $10/day:
[*]Dog walkers...$10-$25 per day, for 1 dog
[*]Dog and kitty day care...$15-$35 per day per pet
[*]Kennel Boarding (small animal)...$20-$25 per day per pet
[*]Pet hotels...$35-$90 per pet, varies with services provided
http://www.care.com/pet-care-pet-care-cost-p1145-q7401.html
Good luck!