I should have given credit to my neighbor. He looked at the sticks I was using to support the raised hatch and said "you need gas struts".
As another after thought, a 40V lawnmower battery provides boon-docking electricity for a 12V and USB power system I installed. This system is described here:
viewtopic.php?f=30&t=74583.
The 240 watt-hour lithium batteries weigh together 5 lb. It provided several nights of plentiful light and a few cell phone and fan charges on a single 40V battery charge. When not in the trailer, I use it to mow my lawn.

The battery holder has a step down transformer to give 12 V output. I added two USB ports as well.
I put 12V LED light strips in the cabin and galley.

I like the idea of solar. I have not seen a way to charge these batteries with solar. Most products I have seen are specifically for 12V batteries not 40V.
As it is, I have not depleted the battery charge on trips of several days. Maybe I don't really need solar.
Power tool batteries are certainly not standardized. Each brand has propriety battery chargers. The available products for my battery use only 120-240V AC and too many watts for my anemic inverter. I have seen some descriptions on the web about DIY charging. It all seems like a hack to me. I don't want to destroy my battery.
I am still finding ways to tweak things on the trailer. The thermos holder is an example. It prevents catastrophic spills. We put some shelves in the cabin to hold personal items at night.
We have a compact folding charcoal grill and charcoal chimney. I have been storing the dutch oven in the car. The small fold-up table is nice since it stows well and lets me cook sitting down.
In this picture I am showing a double burner propane stove. We have replaced this with a single burner Coleman model 576 white gas stove purchased new in the 1970s. It saves several pounds, takes up much less space and provides plenty of heat output for two people.

My old white gas stove was a bit unstable when I put a large pot on it. I fabbed up a few pieces of 3/8" nuts, bolts and rebar to yield a much better cooking support.

This disassembles to stow with less space.

Tom