You're right on the 1800. With the gearbox gone direct coupled should be good.
Not entirely sure if that would be the 'sweet spot' of that motor, but should be well in its operating range.
I'd build and mount it to a skid of some form with lifting provisions to place on a trailer.
Semi permanent, stationary, but able to trailer or pickup mount. It's going to be a bit chunky to lift, but would be too small for a dedicated trailer IMO.