Something with wheels, an axle, or the wheels can be bolted to something.

[Gravydoo II]

I got this bigass thing I cant move cause its so damn heavy and awkward. So, I want to put it on a frame and some wheels. Casters will not work. They need to be like a hand truck with an axle or individual wheels that can be bolted to the sides of the legs/cart frame.

Needs to be able to hold up around 200lbs.

So far I have thought of these things:
Push mower (cause they got them back tires that raise and lower with the little bars)
Box dolly.
generator frame

what else comes to mind?