For those of you thinking about it, here's my result..
Thought about leaving my awning but decided against it since it must come off anyway to remove the RTT. The only thing I left on my rack is my solar panel. Probably removed ~200(or more) lbs.
So two cargo boxes, my RTT and awning are gone, and I went from averaging 11.45 mpg to 13.2mpg on my first tank. Still awful, but my tires and lift are still mpg issues. Weight is probably still a little high as I still have my normal camping kit inside plus my armor bits.
edit: one thing to note, the 11.45mpg was my last trip a couple weeks ago and was mostly highway. the 13.2 was city driving, so I imagine I could see even better results if it were 100% apples to apples..
submitted by /u/fidelityflip