Need advice for my floor pans...

[Destructo]

I was planning on installing a new head unit and 2 12" subs, well, its turned into a fix the rust in my floor boards and replace all the insulation and flooring instead, except I won't be getting new insulation and flooring until I pay to have the windshield replaced and I fix the vent on the passenger side (anyone know if I can get a gasket for it?). The windshield seal is bad and leaking on the driver side and the previous owner obviously used this thing on the beach so everything has sand all over it, the channels for the weather stripping at the bottom were full of sand/dirt and right on the edges is where the rust is the worst, not all the way through but its eaten some metal away, I wanna stop that BEFORE it gets worse.

I plan on putting in dynamat all the way back and up the back of the cab and a full carpet kit instead of vinyl, so once I pay to have the windshield replaced and fix the other leak i'm gonna pick up some carpet and dynamat the crap out of it. Oh yeah, and then install the sub and head unit, actually i'm going to do that before I get all the carpet and stuff. Its gonna be so nice and quiet!