Interior Work Continues

Yesterday I remove the passenger door to fix the outside door handle, since I removed the mirror to allow the door to lay flat, I took the opportunity to spray paint the metal parts of the mirrors. Most of the paint had chipped off, I used a brush to remove the rest of the loose paint, and to scuff the surface. I used two or three coats, from a you don't really notice anything other than normal black mirrors. Much better than the rough silver metal.
Today I removed the carpet and Katie steam cleaned it after it was removed. I worked on some rust spots on the inside, mostly on the front passenger floor. I used a rust converter. It was weird because it sprays clear/white, but turns color after it contacts bare metal or rust. It takes 24 hours before you an top coat over the rust converter. I plan on using some aerosol spray truck bed liner on the floor. I am debating a few issues: 1. Do I put the back seat back in?; 2. Do I "bed liner" the entire cargo area?; 3. Do I "bed liner" the entire inside?
Wal-mart has a gallon size roll on/brush on liner for less than $50. I think I might do the cargo area, and then put the carpet back in the passenger areas.