If I am not an American citizen, can I just work for free facilities?
Coleen, the working while RVing editor replies:
Donna, you may be able to do some volunteer work where they provide you some use of the campground or other facilities. Check with the particular non-profit, charitable, educational, or government agency that you are interested in volunteering with to find out their requirements.
As for a job in the private sector, to legally work in the USA you need to have the proper paperwork. I'm not a lawyer and can't give you legal advice, but I don't think it matters if you are paid by check or if it is a barter situation where your compensation is the use of the facility.
Go to the Workers On Wheels Work for RVers and Campers blog.