Gas mileage, environmentally friendly remodel

I want to remodel my coach and lighten the load in order to get better gas mileage. I'm planning on a environmentally friendly remodel. (This is my one year plan after repairing my leak for those who followed that post) Things I've been thinking about are: The furniture weighs so much. The mattress in the back is on a thick piece of plywood on cut off 2x4's. The 2 swivel chairs, though very comfortable are heave and so is the fold down couch. The only thing about the couch is it has seat belts which we want to keep. Get rid of the AC unit. Switch out the Fridge and Stove when they no longer work. Get rid of the carpet and install cork flooring. Another thought I had is a composting toilet instead of a black holding tank, anyone installed one of those? Bottom line, is it worth doing this and will it really increase my gas mileage? Thanks for the replies in advance.