Mine would get wet all the time till I traced to the the water flowing down the black strips (rain/washing) on the roof into the back window. The sealant in the window must have been old and cracked. I pull the rubber window trim open like a hotdog bun and used a big tube of silicone sealant and went around the top and sides and have not had a problem since.
To dry I would use a box fan and run a couple sections of vacuum tubes under the carpet what I couldn't pull up and let it run all night, by morning it would be dry.

If if it happens again try looking there.