Is extending the level part of the drive the required distance needed for clearance an option? I am under the impression that the trailer’s contact with the rafters is pretty near exit? You don’t say if the RV port is attached or unattached, but I would most definitely consider extending the level part of the drive as opposed to extending the height of the roof if the RV port is attached to the house.
2012 Rockwood 8314BSS
Camping, Dutch Oven Cooking, and Homebrewing