Caulk is good for now but in the spring you might try eternabond. Here is a photo of our rear corner repair.
I took off the metal trim to the top but let it hang, then used 2 2" strips of eternabond overlapping the corner then rescrewed the trim using new stainless screws and replaced the vinyl strip.
Another way to put pressure on to straighten or hold a glue joint is to use a scissor jack, you might have a couple to stabilize the RV when parked.
Ours were brand new here. We used the car to secure against because it was the right height. Here I was gluing the filon back on a lower area repair.