How much do the 6 of you weigh? (and how much will it increase in the next 5yrs)
You are probably in the 7500-8000lb range by the time the trailer is fully loaded with a 1000lbs on the hitch. Add in 600-800lb of people along with another 300-400lbs of stuff in the truck and you are well over 2000lbs. Does the truck have that kind of cargo capacity?
Obviously, exact info on the trailer, truck and loading would be helpful. If you travel light with tanks empty and it's 2yr old quadruplets and the wife is 98lbs, you are probably within ratings. If you are a well fed family with 4 teenage boys averaging 180bs, I could be underestimating the loads.
No you don't need to go 70mph to be safe. Just avoid major cities at rush hour and 55-60mph is fine. Climbing hills trying to maintain 70mph is just a waste of fuel. Get in line with the semi's and chug to the top.
X2 that there is no point in putting in a 15% buffer. The manufacturer already provided a safety factor when setting the ratings. Unless you plan to increase the trailer size in the near future, there is no point.
