Joseph, its good to see you back on-line. Your posts were very inspirational. I go the impression that before you worked at a machine shop that allowed you to work on personal projects on lunch-break?
Glad you achieved personal goal of backwoods property, but does that mean you have no access to a shop?
I was and am still enthusiastic about Stirling engines, but after re-reading this thread, I want to emphasize if somebody makes one and gets it to work, it will be very big and heavy, and the power will be small (like a VAWT?) and I only anticipate being able to charge AA, C, and D batteries for LED lights and music.
A simple one-atmosphere engine should have a "suck-in" relief valve, because after heating the air (pressure) and some minor leakage, the cold part of the cycle will eventually draw a partial vaccum, and slow to a halt.
It is important for efficiency to have a small internal gas volume, so, heat exchange is vital. Cold-side works well with water jacket. The original Rider was used to pump water from a well up to elevated water-replentishment towers on the steam-train lines (in places that had inadequate wind to use the preferred wind-pumper). The water-flow cooled the cold side cylinder as it was being pumped.
The other popular application was hotel water cistern pumping and heating. A low-wage boy would start a fire in the Rider, and it would pump and heat water to the elevated tank, which then overflowed into the cold-water supply tank.
This provided warm and cold gravity-feed water to the hotel rooms. When the fire went out, the Rider stopped pumping. Just before WW-one, they were widely replaced with better performing electric motors, and were melted for scrap.
If you don't have a total-loss water supply (like a solar Stirling in the desert) you might consider having the water-jacket flow through an elevated loop with a vented expansion tank at the top. If the two columns of water are equal height, and the down-flow leg is made of cooling radiators, there will be a thermosiphon effect, and any water pump thats needed can be very small.
If a small water pump is needed, it would not be hard to make a seal-less magnetic impellor to eliminate the shaft with its leakage and friction.
If you do everything "just right" you will end up with a large heavy machine that consumes a lot of fuel and makes a tiny amount of power.