I saw some folks in my area cover a mobile home with a whole new roof structure.
I guess that the original roof was beyond repair, so they framed out a new wood structure directly on top of the old roof [with no demo to the original roof], and finished it off with metal roofing.

I'm apologize for going off topic... as I know that solution is not a cheap or temporary fix.
I just thought that was a great idea; and I bet the home is now a lot cooler in the Summer too.
Maybe that could be a consideration when you're ready for a more permanenet fix.