My biggest concern with the truck is the Drum breaks being over heated by the aditional weight if the trailer breaks are not up to snuff. Get a GOOD break controler like the Jordan or the prodigy and if the truck brakes are up to snuff you should be ok on that front.
Next question is engine size in the truck. 252 and 292 I would have some concern but should be ok otherwise.
Lastly is the gear ratio. In the 60's GM wasn't so timid about putting in some gear because it was before the gas crunch. You probably have a 3.73 gear and you should be fine.
Trailer is going to be about 4,000 lb loaded simular to our Caravanner. Our caravanner has bad manners without a sway control of some sort. Single axle trailers with a lot of isde area seem to have this trait. Don't even notice it with the sway control.
I would recomend 750lb weight bars and Dual cam Reese set up. Seems to work very well on ours. At the very least get a friction sway control.
1959 22' Caravanner
1988 R20 454 Suburban.