What's the Combined Vehicle weight of the F150, what's the Tow rating? Both should be in the manual
The difference between a Nash and an Arctic Fox (for that year) is the wood used in the cabinetry, the framing and that's just about it. (As I recall they had gone to Filon on all Nash's by that year)
These are HEAVY rigs, well built, but really heavy. I would not be surprised that the trailer (loaded) would exceed the ratings of the F150.
A thousand pounds is about right, for a weekend (including water). But low for a family of four for a two week vacation