Wwn thanks for all the quick replies! I figured it'd be a few days before I got any advice but instead received multiple great replies!
Yes, I have figured out where the leak is coming from and tore into the side wall somewhat. There is a seam in the filon exterior halfway up the front window and pretty sure that is where it is coming from. The main frame is built out of metal square tubing and has some substantial rust going on. Instead of cutting it out and replacing, I'm going to clean it up and hopefully just scab onto it with new metal angle or flat.... whichever will work best when I get tore into it. I may get tore into it and realize I'll have to just replace it, not sure. That being said, the walls are in fine shape other than bottom square tubing.
I. Was hoping to wake up to warmer temperatures today, but even though it's above freezing, the wind is blowing 20+ mph and makes it pretty chilly. I may try to get out there and tear it apart this afternoon. I work 12 hour days and would like to allow the plywood and glue to dry for a few days and then hopefully this weekend start rebuilding it... probably too ambitious but it is a goal ha ha!
I greatly appreciate the advice thus far! It's really nice to hear from people that have been through it already as well!