I just replaced all the window gaskets on our 71 Safari. No big problem if you enjoy impoving something. Ordered the gasket material from Andy at Inland RV. Estimated the total footage needed plus a little extra. Used black adhesive also from Andy. Pulled off all the old that I could and then with a putty knife and chisel, scraped off all the remaining. The problem comes when you have raised the windows as high as possible and that isn't enough room. Therefore, since I was at it, I replaced the screens also. Thereby, gaining access to the top from inside the trailer. Glued in the gaskets and replaced the screens using the old screen inserts.
Looks better and seals against weather and dust while on the road.
What else are you going to use your time for anyway?
Dan in Tennessee