When I was 100% stock, somewhere in the neighborhood of 22 mpg on really really boring flat highway over a tank. Typically cruise at 70 mph. Measured at pump. Stock GY HP 235 65 17s. No i don't fold in my mirrors. Typically see above 20 on highway. Like to keep revs ~2K - 2.2K when cruising. 4 speed auto.
Not a clue about city, too many variables, sufficient to say not good.
There is a big drop off in mileage when I push it above 80, was doing ~83 on the interstate for a couple hours this summer with 500lbs of gear in the back. easily in the 18 mpg ballpark trying to make our way home.
No clue with the lift. Get back to you when i get real data. Winter tires going on next week + cold so numbers might be biased.