As the load gets heavier the advantage goes to diesel for better mpg and ability to haul/tow.
Gas work good under lighter loads. Gas will get better mpg unloaded but loaded it will not do as good as a diesel when loaded. Gas may, MAY work better for you based upon what you wrote.
My Camper tips the scales at over 5700 lbs full loaded for travel. Here is what you need to know: There will be a sticker on your camper, usually outside and it shows the base weight, then the As BUILT weight, not add to the as built about 600+ lbs for food stuffs, clothes, etc etc water in tanks etc. This your TRAVEL wt. You can find that at any CAT scale at most truck stops. Drive on and for about $12 bucks you get your load weight by the front and rear axle and combined.
As you are going no slide and short bed big weight savings.
As for trucks, I always had Chev/GMC, but when I need to make the move to heavy duty hauling, I ended up buying Ford F 350 and as a engineer I compared them all and Ford is the best truck out there at the F 350 and above level.
You don’t normally get swaybars on stock trucks unless you get the Camper Package and I would say that is a MUST! It Certifies you truck to carry a camper!!! Ford has it and I am sure other makers do.
Do not know where you live but for a real super deal on a Ford truck if you want to go new. McLane Ford, Fredericksburg Texas is hard to beat: They sell trucks at Invoice minus any Ford discounts to which your eligible. I just bought my new truck and Invoice minus $3500 dollars due to eligible discounts. In addition they a clean deal, that mean no lifetime window tint or steering wheel wax or muffler bearings. Its owned by a Texas rancher, only got a couple of sales guys jeans boots place. You would love Fredericksburg, old German town, now a tourist mega small town great place to visit. Over 143 wineries, breweries and distilleries to visit in the Texas Hill country. https://www.mclaneford.com, Matt Self is my sales guy, I get nothing if you buy there. Bought a lot of trucks and cars and never been treated better or got in and out faster. I know the owner, have his personal phone number, just the kind of place it is.
If you buy new then here is a build I did on line that you can look at and I recommend you click on ‘Summary’ and look at the options. I built it to do what I think would work for you based upon your input. https://shop.ford.com/build/superduty/#/config/Config%5B%7CFord%7CSuperDuty%7C2020%7C1%7C1.%7C613A.X3B.148.N1…XLT.54F.4X4.SEC.85S.67E.YZKAA.X3E.68D.471.17V.SRW.TDX.350.CBB.%5D
Let me know, I will guide and and help in any way I can…
Seriously consider living in a camper, it is small when there are no slides and a short bed also. There is a reason why many people buy and regret or upgrade if they can afford it, because it was to small to live in. If you chose no slide, then I would recommend a long bed for a longer model. DRY BATH! Even as an Infantry soldier who has taken baths in any place he found to be somewhat wet, creeks, rice paddies, hard rain etc, there is nothing like a good hot shower in a space that is dedicated for it.
I have dated several nurses and I understand you view, but the camper is you home and you need freedom of some space and the cramp of wet baths and barely being able to turn around. A short bed truck is only 6 ft long for some truck, the F 350 is 6 3/4 ft.
If you are on Facebook here is a truck camper group you can join and get tons of help: https://www.facebook.com/groups/722631361410607/
US Army Retired
2019 F 350 CC-LB King Ranch
Hill Country of Texas