Bar Keepers Friend is good on Alum. windows, with a stiff brush. I too have those windows. Have a thread on refurbishing my 77 scamp http://www.fiberglassrv.com/forums/f56/refurbishing-my-77-scamp-51268.html
note I said refurbishing, mine is pretty usable as is but needs some work to deal with the years.
Donna's link here or on my thread will lead you to a source for two parts you need. The plastic strip that wedges the plexi glass in from the outside and seals the glass. And the rubber seal that goes on the inside of the window frame to seal the window when closed.
That wire on the arm may be because the clip that the arm folds up and locks behind is missing. May have been used to clip the arm "up" to latch the window. I don't have anything but the rubber ends on mine.
I find those green plastic scrubbing pads work pretty good to get caulk off. You will learn to hate silicon caulk.
store online has the butl putty tape that is normally used to seal the window to the wall of the trailer. If you call in your order sometimes they can ship US postal which is cheaper than the online UPS shipping. They still have a lot of basic parts which is really cool if you ask me.
Those window prop arms are like gold. Only way to replace them is to find a scrap window. There was a thread here on buying ones from Vintage Trailer that are not the correct size but a machine shop or maybe welder can re-work them. If you know someone who does art work in metal....
Don't sweat finding the screen spline (rubber tube) that holds the screen in. They make that stuff in massive number of sizes, just take sample and look for places that repair screens. While your at it see if they have alum. screen or plastic. Steel screen and alum frame cause mutal corrosion if in contact with each other.
You can use epoxy to patch rivet holes, just spread thin on back, scrape of excess on front, once it hardens re-drill. But wait until you have rivets to see if you need to patch, rivets can self adjust a little.