We are two months into our trip and here are a few ideas that are really helping. We are in a 2008 1500 Silverado with a 5.3 liter engine. The trailer is a 18' by 8.5' weighing in at 5850 pounds loaded. The tongue weight is 580 lbs. We bought the trailer with one piece roof, extended tongue, floor joists at 12 inches, .030 skin thickness, 5200 lb axles, upgraded tires, and led exterior lights. Trailer $5250. We put $9000 in into the build so we have$14250 in the trailer. We are going to be living in this trailer for the next couple of years for 6 to 9 months at a time.
The first is the transmission cooler we had installed. The truck had a small 4" by 7.5" transmission cooler but we had the largest that would fit installed, 10 or 12" by 15". It is hard to measure the new one. Even going through the Smoky Mountains and part of Shenandoah at 70 mph up and down those hills, gauge showed 207 degrees is the hottest temp reached. It was about 92 degrees that day. The Reese Steadi-flex Weight Distribution, With Sway Control hitch for 6000 lb trailer with 600 lb tongue weight. Going down those hills passing and getting passed by Semi trucks at 70 and 75 mph that trailer does not sway at all. My wife even has no problem driving under those conditions. Our normal travel speed is 60 to 65 mph. We are averaging 9 miles to the gallon of gas.
The next item is a wireless camera mounted on the back of the trailer with a monitor inside the truck cab. At 8.5 feet wide we cannot see vehicles approaching from right behind the trailer. This camera lets us see cars at least 200 yards behind us. So we have peace of mind when we change lanes. Our monitor is only 3" X 5". But it works. It also works as a security camera at night as the camera is IR and we can unplug the monitor and move it inside the trailer. This package is from Tadi Brothers and we have had problems with the monitor, sent it back once and it still sometimes shuts off for no reason. The camera is flawless. There are cheaper versions available on Amazon that might work better.

Our bank of 4 Trojan 105 six volt batteries gives us power for 5 days and 4 nights of boondocking and the power only got down to 67% . You should never get down to below 55% on lead acid batteries. Our fridge (Engel) runs 24/7, Maxxair fan runs all night, CPAP runs all night plus water pump, interior fan and lights as needed.
Suburban 6 gallon gas/electric water heater. We have used the electric only once. We have used the propane to heat the water the rest of the time. Our propane is in a sealed box that is sealed and vented through the floor of the trailer. It is located in utility room at the back of the trailer. We only turn the propane on for cooking and showers and then turn it off. All our propane lines are inside the trailer. We check once a week for propane leaks. Our shower is 24" X 27". For someone 68" tall weighing in at 191 lbs this is a very nice shower size. We do not spend a lot of time in the shower so no need for a large shower. We have no gray tank for our shower, we just catch it in a bucket. This is how I know that we both use a little less than 2 gal per shower. So 4 gallons for us both to shower. We use an oxygenic shower head. We run the water heater for 12 minutes shut the gas off and that allows us both to shower without wasting gas. We get wet, turn off water, soap up and then turn water on to rinse. This is a very nice "boat shower". We do catch the water that comes out cold at first, to wash dishes. We have a 30 gallon water tank. We also use 8" X 12" disposable adult wash cloths to save water if we are not dirty or real sweaty. They work great also. We do have a 12 gallon gray water tank for the two sinks.
Our Sterling power battery chargers work fine, one is battery to battery and the other is a standard programmable smart charger. The standard charger is 10 amp so it will work with our 1000 watt Honda Generator. Our window unit A/C will also run on the generator. All lights are touch LED so no switches. Our stove is out of our boat, it is a Dickenson propane stove, two burner. The 2" of insulation in the ceiling, 2" under the floor and 1.5" in the walls work well. The floor insulation really does help. The 9' awning is very nice also
If you have any questions we will answer them. We will be in Shenandoah National Park for 4 days starting on the 14th so if we have no cell it will be after that before we can answer questions. We are trying to visit all the National Parks over the next couple of years. Our build is located on this page as ris 8.5 X 18 new trailer build 11/1/17. We have a blog at thejillkristy.wordpress.com
If we are ever near you come by for a visit. The blog always lags behind were we are but we usually let folks know where we will be next. After 4 days in Shenandoah park we are headed for the eastern shore of Maryland.
Richard