Hi Beachnut, we just purchased a 5245 as well. I would be very interested in knowing what modifications you have made to yours.
I have made some mods as well; notably creating a place for storing the sewer hose within the sewer compartment, added support struts to the overhead cabinet doors, added aluminum angle support behind the center brace in the wardrobe cabinet, opened under the dinette seats for additional storage, and working on the bed operation.
The units need some work to be fully usable. I would love to swap ideas and issues to see how to take the rough edges off.