I am not sure I am going to be any help or if our units are the same, but here is where I would look on my Palomino Solaire 147x based on what you said.
Check the gutter above the door and make sure the caulk is good. I think if there was an issue here, water may possibly get under the gutter to the door and then past the gasket.
Check around the lights above the gutter to see if there is a way water is getting in that route. Maybe the caulk between the light and the camper is missing and water is going in that route.
On the interior of my unit, my front speakers and bunk fan are attached to the ceiling near the bunk door to a piece of trim. Does that piece seem wet? Maybe if you are handy and can remove it you could see it from that side to see if it reveals anything. Or if your speakers are there like mine, you could at least drop them down and see if it reveals anything.
Don't know if that is much help but a couple of thoughts....
2011 Chevy Traverse
2014 Solaire 147X