Sorry for your loss Richard. In-laws had a house fire (total loss) some years back and the fight with the insurance company was epic....so I can imagine yours was as well. Only hope your settlement came somewhat close to the loss.
My shop started as a 24x36 I basically built with a chainsaw/sawmill lumber, as we had no power to the place then, and I couldn't afford a generator. We had to throw it up quick, as we sold our house in town and moved a mobile home to the farm. The loft of the shop was storage for all the stuff from the house that wouldn't fit in the small MH.
Worked out of it for 10 years, cussing the 8' ceiling every time I'd swing a board vertical, so by mid 90's, we were in a better financial shape to build a bigger shop.....plus I'd bought a Woodmizer sawmill and was able to cut a lot of the material off our place. Tore the original shop down, extended the slab 50' so the new footprint ended up around 35 x75.
Most of my shop use is wood working, so that was the focus. Did put an oil change pit in the front part for access under vehicles for oil changes/etc.
Ran a 9" pipe under the slab for dust collection at machines, connected to a 3hp blower outside. My thinking is it takes less to suck down/out than UP/out like most collection systems.....plus I wanted as little overhead to collect "fine" dust as possible.
Inside, over the top of the pipe, I arranged for table saw, jointer and planer to sit with 4 & 6" takeoffs the main pipe for dust pickup.
More recent photo. Old red wood stove burned out, replaced with a bigger one. 15" Grizzly planer replaced with a spiral head 20", added a stroke sander on right wall & had to mount a fan in that wall to help with the really fine dust that comes off the dust collection doesn't pick up.
Keep the back 12' of the old shop, and turned it into a work/reloading room, a storage room, and a dry kiln (the door on the left back). Kiln uses an old window AC to dry/dehumidify lumber.