Let's be real. If you don't have a valid VISA/Passport/WETCA than your options have just decreased to almost none. At least in my experience. I'm sure it's possible and, i don't want to discourage you but, If you get stopped even just 1 time by the cops, which in this life is a 100% certainty, you are done. I don't see you being able to fly a sign or spange and lasting longer than a month or two before a cop tells you to move along, but not before carding you. Best bet would be to get a job under the table and stay off grid in that sense. But if you are adamant about going this route I'd stay in the bigger cities where the tolerance threshold is much much higher. You'll be messed with less. Like I said, there may be other ways I just don't know of them. Best Advice, if a cop asks for your ID, run like hell. Keep in mind that deportation/extradition from the US+ will not be as simple as them sending you on the first Plane Back. You could be in detainment for anywhere from a month up to over a year before the extradition order goes through. Good luck. Hope it works out. Wish I had a house in Mexico...