Removing and replacing the windows is not all that hard to do. I removed and replaced seven windows (two really large ones over the couch and dinette plus the cabover and four smaller ones) on our old coach.
I removed and replaced them the way George mentioned in his post, except I used butyl tape instead of putty tape and then used a bead of 3M 4200 around the top and sides to insure we had no leaks
Whichever way you go you'll be better off than you are today as your coach will not leak when standing still, which if it's like ours is most of the time! You can always keep some towels ready for the occasional rain while driving