Ok, will throw in my two cents, why not everyone else has (Lol)
Ok, I have towed a **** ton of trailers (goosenecks, bumper pulls, RV's, equipment etc etc.) What no one is talking about I will address.
First thing, (starting from the rear going forward) check the trailer bearings, I have found that new trailers come with minimum amount of bearing grease so check that.
Dual axle trailer, when loading it, load it without the bar in place--This is IMPORTANT! what you are looking for is weight distributed properly in the trailer, you will need to look at the pivot between the front and rear leaf springs, it should be tilted backwards about 30 degrees when having a 60/40 weight distribution, that being 60% weight forward towards the tongue. Many people over look this and have either too much or too little and wind up loosing control.
When packing luggage etc. I always put it (stow it) on the floors, I never stow stuff in the upper cabinets when pulling, the lower centerof gravity the better.
Check your trailer tires, that they have the proper pressure--unloaded! I look at the sidewall max pressure at load if its like 60psi, I would inflate 10% below it unloaded, it should allow for expansion etc. Too low a pressure and you will over heat and blow them.
Your trailer hitch-- Is a load leveling hitch, not a sway control hitch, it keeps the truck level with the trailer, thats its design. Read the documentation on the install. I had one for my 34 foot travel trailer, the bars were installed pointing downward 30 degrees then lifted into the brackets with the helper bar...but that was mine. if you adjust them level before putting the bars into the brackets they will not work properly, they are like a torsion bar when installed.
Truck, check for proper inflation in your tires, NEVER--NEVER use the inflation pressures on the door! those numbers are for stock tires--if you still have them. I run commercial tires on my trucks load range "G" at 100 psi, I would get mine rotated, the truck would roll out looking flat, that tech would use the door pressures---then had to educate them!
Proper inflation is key to a good haul.
Check your fluids, enough said there.
Hauling, Trailer speed is 55mph, not 95mph! I cannot tell you how many times I get passed by some moron going 85-90 mph!! So what, so you can drive 85mph,,but the trailer isn't made for it! Trailer tires are not designed for those speeds,,when you blow a tire at that speed,,well be prepared to lose everything and even someone you care for!
I never pull over 55mph. In some states, if your doing 65mph with a trailer you will get pulled over.
When pulling on hills just watch your temps, if the hill is so steep that you end up slowing down alot don't worry, you are not in a race and people can go around you--you should always be in the right lane!
If your speed falls to 45mph use your hazards--its the law!
Ok,,,thats it for now, get setup right and you will enjoy your vacation free from issues!