Makes a good little puzzle if you got the time...
Here is what I would experiment with and only if window brand is a Hehr. Don't know about other brands. Number one...Write down the little tiny numbers at corners in case you break window.
I would take window out of rv just to make it easier to work with. Remove garnish ring and remove the hole thing.
There's a reason why the slider rides is on inside track and fixed window is on outside track and reason why the fixed window are facing front (toward the rain). And a reason why weep holes are at bottom.
You would also have to flip the center bar with the weather stripping to keep it towards the front. When you drill out the rivets keep one to match up the size when shopping for them because you might not have enough room for larger rivets.
A lot of work and to think about.
If it all works out you'll gain a little more ventilation. I would just leave door open longer or install another fan under range hood. Have you looked into those maxi fans?
2003 Majestic 23P... Northwest travel machine
2013 Arctic Fox 25W... Wife "doll house" for longer snowbird trips
2001 "The Mighty Dodge"... tow vehicle for "doll house"