Right Peripatetic Pull. We stayed at the convention center. The parking area is actually a city park that has controlled security, entering and leaving. We were at a convention there. We parked in the parking area and then went directly to the offices and spoke to the director. He said there was no problem. During my nap the first day, I heard noise outside, only to find a maintenance man wiring up a lamp post with an outlet so we could have electric. Really nice people. We stayed a week.
On edit, having a camper van, I would talk to the guards first. You might get lucky. If not, I have a friend who lives in Morelia who wouldn't mind a few nights in his driveway.
