Hey there Irene,
My name's Melanie (my partner Michael actually talked to you on the phone the other day! I've been meaning to call you). It sounds like you have quite an amazing thing going over at Sahale. You're doing great! Educating yourself, advertising on growfood.org is a great place. Also, google ATTRA and you'll find a whole slew of farm intern/appenticeships all across the U.S. and Canada. Very well organized with information and free to join. WWOOF is also a good idea, I think there's a fee.
As for the legality... from my experience most people know it is illegal... and therefore it is under the table work/not on the books. Isn't it pretty crazy how the government has us tied up in money and threat? "No transaction can be made without us knowing!" I look at it as small, community transactions. Think, if your community changed to a local currency, how would you write it on your taxes? I dure don't know how that'd work... but just think of the exchange as a barter. So many cultures have used bartering before the monetary value of the U.S. dollar came and overtook, or gold before that. Remember that money is not the only thing that holds value, diversify value! I believe that an exchange of work for a place to live and fresh food grown is well worth it and it is how many internships on farms seem to run.
I just rattled on for a bit, but I hope you find these words to be calming and not alarming! Keep manifesting your dreams and goals with intention Irene. It will all come with ease, no need to worry. It's already happening