Hi Maggie
Doing our front window was one of the first projects on our Trill.
Experiment with a side window first. They both are done the same way side is just smaller.
Inside, unscrew your curtain hooks. Carefully pry the ensolite out from behind the window frame. The frame will not move until all the ensolite is out of the way.
Outside, take out all the screws and use a knife to go between the frame and the
fiberglass to make sure the caulk is all loose.
Once this is all done the window should be wiggly and you should be able to pull it out.
Yes, we replaced the whole one side and about 6" top and bottom of the wood around the front. It was non-existant. We used a hardwood 1"x2" replacement to match the original. Cut to lengths. Originally it is glued in place but we just used caulk to glue it in. Once the screws are in place its not going anywhere anyways.
Make sure all the caulk is off the old window frame and the
fiberglass. Lay the strip (comes in a roll from your local RV shop) of caulk all around the window. Match up the holes and screw back in. Use a knive to remove the excess around the edge. Then caulk with a non silicone caulk around the whole edge. I say non silicone but that is my personnal preference. I hate the stuff.
Your done! Good luck.
Nancy