$520 a month after your fixed expenses is not much, but it should be doable. If you spend $250 for food, $50 into an emergency fund, $100 for gas, that leaves you $100 a month for entertainment and miscellaneous. It's a lean, tight life but I think it's possible.
I'd thnk about getting a New Mexico State Parks pass for 8 months out of the year. For $225 you can stay at any NM state Park for the whole year for free. Most of them have showers and for $4 per day more you can get electric to charge your batteries. They have lots of high elevation parks that would be cool all summer. The other 4 months when it's cold, go south to the Texas gulf and camp right on the gulf. That's a good life!