2000 Ultimate Advantage has a fogged center 18" x 47" window on driver compartment. The 3 window frame has come out. $500.00 would replace the one window, but I have separated the 2 panes and scrubbed the panes clean.
When I went to reassemble the 2 panes with the spacer, I found the windows are not square. They measure 47 3/4" x 18" and the other end is 47 1/4" x 18".
Just a heads up if you want to save $500 plus installation.
I am also in the process of working on my bathroom window to defog both the stationary and sliding windows. I found DIY RV Solution (https://diyrvsolution.com/). They have great video instructions and all the supplies to take everything apart and back to together.
In my case one pieces of glass from the stationary and sliding windows is being replaced.
2005 Adventure 38J with 43K miles