Recommendation - patching interior wall

[Goody146]

We recently purchased a 2003 R Vision Travel Lite and the previous owner did not find the best solution to patch the interior wall. There had been water damage rendering the porch light inoperable so they removed that fixture and then used a fiberglass patch inside to patch the hole, heavily lapping on some type of black tarry sealant. Scraping and solvents are useless so looking for recommendation outside of painting over with KILZ or PPG Gripper. Maybe we'll just have to resort to a sheet metal patch and picture or white board to cover that...
Thanks in advance!

[pitch]

Without seeing what you are working with it is hard to asses a path.
I think I would trim out the hole and start from scratch. Since you mention water damage, I imagine that this trailer is not of concourse quality.
You should be able to find a piece of wall board the you can cannablize perhaps inside a cabinet. Also I would find some self stick wallpaper or vinylcover that would co ordinate with what you have.
But that is just me, Frugal and always function before form.