You asked about mpg and how safe we feel.
We expect to see 15-17 mpg towing in normal conditions at 65 mph. If we reduced the speed to the 55-60 mph range I am certain we would often see 20 mpg. When not towing on the highway we expect 27-30 mpg at 65 mph.
Some years ago we had some concerns about stability with our Ram 1500
Reg Cab 120" wheelbase pickup. When semi's passed, or their were strong, gusting crosswinds we would feel pushed to the side. Never any sway oscillations. We installed a ProPride hitch on the truck, now use it on our EcoDiesel and would not tow a bumper-pull travel trailer without it.
Our truck/Airstream is absolutely rock-solid, semi's and sidewinds are nothing, traveling down uneven, rough, narrow secondary roads meeting trucks has no drama at all. Absolute confidence, the truck handles at least as nice as when without the Airstream attached. It is a very relaxing ride.
Safety is also about proper loading and load balancing in the truck and trailer. We are very careful about it, and after 50 years of camping and lots of travel we have learned how to do it (for us).
We do not carry excessive gear or supplies about the country, we load our Airstream with heavy gear toward the middle and light gear at the ends. The ProPride hitch is heavy as hitches go but it is also longer creating a longer lever from receiver to trailer axles; our fully loaded Airstream and hitch is not light but adds only 820 lbs to the truck's weight after weight distribution hitch lift is applied.
We load our EcoDiesel fairly light, heavy gear in front of the rear axle to lighten the task of the weight distribution hitch and weight on our rear axle. The weight distribution hitch evens the load on the truck's front and rear axles wishing 20 lbs of each other, and we are careful to not overload them (axle ratings on the door placard are 3900 lbs each). We then go to the CAT scale to verify this and ensure our loaded truck and trailer are within the Gross Combined Weight Rating for the truck, as that is the weight our rig can easily handle based on our own experience with Ram 1500's the past five years.
We don't set speed records up and down steep mountain grades, we hold the speed to not abuse our truck on the way up, and well onto the safe side on the way down, which is varied depending on road, weather, and traffic conditions.
We intentionally chose this truck for it's soft suspension, a better ride for us and our Airstream. We have not been on the "my Airstream is falling apart" threads with grievances, and we feel relaxed after several days' driving. Those contribute to safety as well. Our second coil spring Ram 1500
, it is a great truck to drive at home and when we reach various travel destinations whole on our six month trips.