Very nice. How much $ and who did the install?

You'll want to put a cover over the fan when driving down the road to keep it from spninning up and taking out the coils.

Under $2000 installed. Ready to plug in. Had a guy out of Rowlett do it. He’s done trailers this way several times with issues of wight on the studs due to how those braces fit.
I do plant to put a cover on it to avoid wind and debris. Had him put a 2 ton system on my 12x16 workshop too. Window unit just wasn’t keeping up. Now I can get it down to 65 and it holds in mid day heat.

Both of those mini’s you had installed are Tremendous overkill. Your going to get nonstop cycling and freeze ups . A18000 btu mini is designed for 750 square ft not 84 . Your 2 ton unit in your shop is designed for 1000 to 1500 square ft not 192 square ft .

Sq/Ft per ton varies on the construction of the area being cooled. Heat loads and infiltration vary greatly when dealing with different structures. That black trailer probably isn't insulated as well as something like a house would be, doubt there's much more than a piece of plywood and a good amount of hot air between him and the ground in there.

I'm not saying he's right, nor you, but the 500sq ft per ton might be a good rule of thumb for newer home type construction, it is not a universal rule though. I have clean rooms where we run just over 1-ton per 100 ft2 due to internal heat loads. Cut the cooling off in a 65-68 degree room and they'll be in the mid-90's within 30min's-1hr. And to add to the challenge, they also run cooling year around. But yeah, being stationary and critical environment rooms I have all sorts of cool equipment to choose from for that.

More similar though...I have a 25' cabin built in a 40' connex (175 ft2), insulated better than most houses except the floor. When the sun is on it on a 100+ day the little 8k btu window unit slowly looses ground. Start the day at 63 degrees (lowest setpoint the unit allows) and by 6pm it's 80 degrees in there. . Go in and out much and forget it being even tolerable. Let the sun get off it and it cools right back down and does fine all night, no humidity issues. In the summer the floor is hot, and it's c-c-c-c-cold on bare feet in the winter. Next unit will be minimum 12k btu, maybe more.

To the OP, for such a temporary use, and just to sleep in at night, I'd use one of the portable units. If I wanted comfort during the day (mid-day work breaks to cool off and re-hydrate) in the Texas heat I'd move away from that to something a bit more conventional. I personally detest mini-splits. They work fine, great in some cases, until they don't work at all. Then trying to track down parts and implement repairs can be a total freaking PITA. I'd cut a hole in the trailer somewhere and put a hinged panel in or something of that nature for when you don't need ac, then have a window unit in a panel you could install/remove as needed. That way when the window unit fails I could go get a new one, anywhere, and be back in comfort in a short amount of time.

Now running something off of batteries is another endeavor entirely. Anything refrigerant based is going to come with a decent current load. I'd bet money that a smaller quiet generator would be more cost effective and reliable in the long run.

As for the little chillers everyone is building from ice chests and such, I can see some advantages there, especially if you could localize the area needing to be cooled down to something like a big tent-cot or temp enclosure inside the trailer. However, you do not want to pull the conditioned air directly across the ice unless you want to wake up soaking wet. You could create a heater exchanger within the cooler to keep the moisture out but take advantage of the cooled air without all the humidity. Then you could even use dry ice without the concern of carbon dioxide. Add a properly sized fan and you'd be good to go as long as you have enough ice on hand. Always a downside to everything.

My last lease we had a windmill and water tank about 50' from camp, no electricity. I had plans drawn up to plumb in a tee so i could divert that nice cool water from the tap to our cabin, thru a hydronic air handler, and back to the tank and put a dc powered fan in the air handler so we wouldn't have to listen to a generator run all night. didn't get it implemented before that lease went away though.

I grew up in the AC, heat and boiler work business. And you’re right about the overkill under normal circumstances. I use aCO2 laser in there most of the time. When it’s running, it has an exhaust fan with an 8” vent sucking all of my room air out and fresh air coming in. If I’m not working in there I turn it up to 85. When I walk in to work I kick it down to 65 so it will keep up. Works great without issue.
I did have the walls, ceiling and doors insulated when I had the trailer built. I figure I can open the vent in the ceiling if needed to let some air out in order to avoid cycling issues.