Let me preface this by saying that I did not own a truck or camper when I started. I custom ordered my truck in an attempt to a) maximize payload b) maximize mileage. I was getting ready to retire and planned on traveling. Although I was not planning on any off-roading to speak of I did plan on plenty of forest service roads.
Truck:
2016 F150 SuperCab, Lariat, 4X4 (not FX4), 36 gallon fuel tank, 2.6 liter EcoBoost engine, 2.7 liter payload package (similar to HD towing package).
As someone mentioned before your trim package does effect a lot more than I thought - actually I didn't plan on that. The charts are for the stripped down version that you probably could never get. I ordered the 4X4 package that basically eliminates the skid plates and has a different sticker. On tires. Mine did come with E-rated tires BUT they are not marked as you would expect and I had to have the dealer confirm. My biggest regret ordering the truck was not specifying better tires. I assumed they would be off-road tires considering it was 4x4. The tires have a street tread with no meat at all. I need to replace them. I would strongly advise upgrading. Payload on the charts that I was trying to achieve was 2160 lbs. As built was 1899 lbs.
Camper:
2016 Hawk, front dinette, silver spur. 160W dual battery solar package, single roof vent, cassette toilet, heater, water heater, batwing awning, 130 liter Isotherm refrigerator, jacks, standard stove and sink. I can't find my documents from the scales but the camper with LPG and jacks (no gear or water) was about 1500 lbs.
Results:
I am very happy with the build. As far as mileage, the on board calculator is between 1.5-2 mpg higher than the third party app that I use (GasTracker+ from Fuelly.com). Per GasTracker+: Truck new ( day 1 to 84) without camper was around 18 mpg. Camper installed and never removed from day 85 to present (36,630 miles) gets 14.7 mpg around town in California. On trips outside of California I get about 16.7 mpg average with 18 mpg at times. I consistently see about 2 mpg better mileage once I fill up out of state. Worse mileage returns upon first fuel up within California. It probably has something to do with the magic fuel blends we use. Actually I think out of state fuels use higher ethanol and might account for it.
The truck is stock without suspension modifications. I'm very happy with handling and only notice a sway problem once fully loaded wet. Honestly its not very bad and I don't think I will even do anything about it. I wish the mileage was better but definitely not bad. The 2.7 liter engine has no power issues. I was following a trailer uphill at about 11,000 feet in Colorado and passed it without any problem.
If I had it to do all over again I might, thats might, consider an F250. I feel safe at my payload although I honestly have not re-weighed the rig yet. I am waiting to become more finalized in what my standard gear load will be. I'm sure I am near or slightly over limit. The extra payload never hurts and would allow for camper/gear upgrade flexibility later. Not sure how big a hit on mileage that would be. Also for load perspective, I am an ex-backpacker so my equipment load is minimal. I don't load up with BBQ's, firewood, cast iron pots, tables, etc. (not that that's a bad thing).
Hope this helps someone.