repairing eye bolt tie downs on 2003 Pastime

I've been here awhile, my first question though. The camper is in very good condition, except I need to replace the rear eye bolt on the Pastime 2003 camper. It was a bit loose, couldn't tighten it because the nut was rusted on the eye bolt, didn't know that until I removed the propane tank and housing. So there is about a 4" x 4" area the plywood dry rotted, the 1x3 strip going front to back has about an 8" length that needs to be replaced.
Any suggestions on how to fix? I prefer not to take off the jack siding, and such, unless that is what I should do. I'm thinking an aluminum plate nut and bolted to the good plywood and the new eye bolt attached to that, along with the 1x3 area replace with a good piece of oak. That should/could be stronger than just the original nut inset into the plywood. Any pics, suggestions, directions, advice will be good. Thank you,
Ken