Why not just throw a tarp on it, just big enough to cover the roof only, with a few bungee cords; and remove it when it’s time to leave?
Wouldn't a tarp cause issues with the rooftop AC and vents? Unless you built some sort of structure out of 2x4s or PVC. If it were me, I'd get some Tyvek house wrap, cut it in the outline to go around your AC and other roof penetrations, even cutting a smaller piece to fit over the AC and just hold it down with small rocks or whatever. Tyvek is cheap and just throw it away when you're done.
