I am working on mine also. However, I'm on a really tight budget. I pulled the tracks from my side windows only on the bottom. The cotton material was goo and the metal spline rusted. Yuck!
LEVEL THE TRAILER!
1) Remove old track and clean the gutters. Just remove the bottom track. The best tool for the drain holes is an old pick from the dentist. They might just give you one as they do wear out. The little hook is great for pulling out the stuff that gets into the track.
2) Add a small dab of caulk on the screen rivets. The T area may be in accessible. Or take off the screens and rivet them back on with caulk. I chose not to mess with the screens, rivets only.
3) I am using a stick on fuzzy velcro as a temporary track. I do not put it by the drain holes. This is temporary until I get enough to replace the windows...which really means it will be there in 20 years.
4) While the trailer is outside in the rain, I added a wick to the drain holes to speed up drainage. It is just a 1" by 8" piece of nylon pantyhose. Water wicks along the nylon via surface tension. Any fine grain nylon should work like a piece of twine. After you put it in, test it by pouring water into the gutter. The water should wick away quickly. Simple, but it works.
I'm having a lot of fun with my trailer. Menard's has that silver bubble insulation on sale and I am slowly putting it in. Almost done with the table mod too! I will attempt pictures if needed.