As I commented earlier, let me expand a bit, having been there too many times.
I have a nice '14 F-150, even went 5' bed as it is a HD car. If we are traveling like we are now, staying in hotels/condos, it is unbeatable. Right at 20 mpg with a bed cover and the 5.0. I chose to go with a left over '14 XLT with Lariat upgrades- console, leather, rear camera, etc, and got an honest $14k savings as the '15s went to alum body, etc.
Then I looked for ever for a nice solid rust free 7.3 F-350 CCSB, and finally found one with 170k on the clock. No mods, XLT in need of a seat recover and ball joints. I did the seat, new ball joints, base lined all fluids, new filters, etc and have in it what I saved in the 150.
The 150 got a leveling puck, 35 A/T's and a CanBak cover. The 350 got the guts: 4" lift, 37's, etc, etc for exploring/camping/traveling longer more remote destinations. I vacillated back and forth and have built both platforms too many times, so for me, this has been a near perfect solution. And the 7.3 truck cost initially what the new 6.7 diesel option alone cost. I have had a 6.7, and loved it, but has been said, would hate to have it out of warranty- sooooo many sensors and integrated electronics.
The SDs are bigger, heavier, stouter and ride more truck like. The 150 actually has more leg room in the rear seat (we have kids as well). I also tried a 350 with the 6.2, and it is a good solid gasser choice, albeit a bit thirsty.
I am an old fart, but this solution is working and even solving my vehicular ADD for once!! To each his own, but for the cost of a new truck, there are many many solutions/options- most all good ones. Enjoy the hunt, the build, and especially the travels!