24 hour gasolineras are a good bet but park where it is lit and I buy a couple of the night crew a Coca Cola so they take more of an interest. Don't park where it is dark, and don't leave anything loose in the pickup bed or side hatch doors unlocked. Having a dog alarm works.
Ask a gasolinista where the closest BALNEARIO is. Most of these places bend over backward to accommodate tourists. I carried a plastic pipe when coupled together equaled the ultimate height of the rig plus a few inches to spare. Sure made clearing "Arcos" and trees more sure.