OK going down the list:
I find buying a still disturbing when there is everything you need to make one available for a few coins at the building supply center. plus there is the tradition factor.
Folks around here just continued the tradition of building their stills and processing their liquor when they arrived here from there. There being mostly Wales, Scotland and north Ireland.
Even the teetotalers around here keep a coil of copper tubing hanging in the shed, just in case.
And now that you mention it the thought that SS did not have the makings already on hand is more distressing! I'll bet they are there and he simply does not recognize the proper use of said items!
Whisky is the ultimate calorie preservation method. Plus, unlike beer, cider and ale, it fits into my low carb diet.
Now for the cart,,, are you putting the panels on the cart with the battery and inverter? If so why?
If you have enough panel for decent charging, say 200w, they are going to be too big to put on a cart and defeat the portability of the power pack.
I made a trolley from a 2 wheel movers dolly I got at Harbor Freight for $30. It is the lightweight model and not much for moving heavy furniture but stronger than a plastic grocery dolly by far, and it has inflatable tyres. It also makes less difference how heavy the battery happens to be or even if you have a stack of two. Build a shelf like a book case and stack them up.
Put the panels outside of wherever and run the charging wire to the power pack on the inside to charge. Pull the plug and take the power pack where ever you want it. They all come with universal fittings now. You can move the panels around easily enough if you want to keep the charging up while you use the power pack.
I have a trickle panel attached to the outside of my bike shed, run the wire inside and plug it into the accessory plug. Keeps the bike batteries topped up. Unplug it and roll the bike out to ride, everything is weather protected.
The power access plug on the bike also turns it into a power pack for use with 12v gear. Basically creating a high speed ride-worthy emergency generator.
Way more fun than a trolley!
Of course I do the same thing with my lawn tractor but I can't run it down the motorway.
Which reminds me of the old George Jones incident (Country music singer.
https://www.youtube.com/watch?v=VExw77xJsBQ )
He was arrested for driving his garden tractor down the public street. His driver license had been suspended for DUI and they had impounded his vehicles. He was going to the liquor store.