I won't be using a dolly, changed my mind and am going with the simpler method of using 3/4" pipe from my pipe clamps and roll it along the planks with the lathe mounted on skids. I'm doing this to keep the cg as low as possible. For the most part it is a level run, the only sketchy part is on the bricks. I intend to screw two planks together with cross braces on the bottom to act as one rolling surface through the fireplace/brick path area. Although not a pro rigger I have quite a bite of experience moving heavy machinery so I am confident it will work fine(hope these aren't "famous last words"). With the carriage removed the lathe(bed with headstock all that remain) should just squeak through the 24" space.
Brian
Here are the planks and skids in the "raw", I'll cut and attach the skids on site, then use the cutoffs to block the lathe in place in my truck ; HF hoist ready ready for the trip.