Kojack,
The Ford, 1 series pickup associated with the almost 2 yr. old Lance 650 is the absolute highest rated payload version. This means 2WD; single cab; anemic, high revving gas engine; stripped down; not a lot of extras. Your earlier Ford is not even in the ballpark. In my time on Truck Camper Forums I have seen the subtle and sometimes abrupt paradigm shift of many thinking that one's coveted old F-150 will carry a loaded, 2800 pound camper with stuff with ease. A trip to your GVW and CGVW stamp on the door pillar will solve a lot of woe later. I've seen hundreds of people hoping, just hoping that they can stuff that 6 quarts of RV joy into a 4 quart pickup bed.
Yes, there are a few 5.5 bed TC's available, but let me say this: My Lance 165-s is the lightest, least tall, and least wide of the widely available, wet bath, heater, stove, fantastic fan, queen bed, 3 cu. ft. fridge, 3 gallon hot water tank, small tanks: 18/14/12 gallons, TC's of its time, advertised for a one series, 6.5' bed truck. It has exactly the same advertised 1742 pound wet weight as the L-650. The guy i bought it from added air bags and a bunch of other things to his Dodge 1500 to make it work, and even then it was iffy and close to the edge. The only thing that saved him was it was just he (about 150 pounds) and his 8 yr. old son (about 60 pounds) and no pets on his 2wd, single cab 1 series. We bought it and put it on our new Dodge 2500/4WD/Cummins/camper package overloads truck thinking this was way over kill and it was still too much for the stock suspension even with the factory 3 series overloads. So, I've spent a dozen or more years getting the suspension beefed up without air bags. Now, here's the point: There are only two consenting adults in this small Lance and we have learned to do the Pas du truck camper ballet and sense the moves of the other. Recently we found out again how close to the edge we really are with our 10 yr. old grandson sleeping on the dinette for a week during our annual Oregon Coast kids and g. kids Camping Romp. Just this little waif added to our mature bods made any movement almost impossible. With just two, we have learned to live with it, but it's still tight. I cannot imagine going any smaller. Narrow:
jefe