Nope, septic was not powered up yesterday, but now it is. Really not much left to do except get rid of some lumber, toeboards for cabinets, and finish pumphouse (OK, and fab 6' workbench, install storage shelves, mount downstairs cabinets, etc., etc.). Only the toeboards are on someone else's to-do list. . . .
Based upon seeing some work done with mobile table saws, e.g.:
http://lumberjocks.com/projects/30738
mobile drill presses, e. g.:
http://community.woodmagazine.com/t5/Tools-and-Tool-Buying/Mobile-Base-for-Drill-Press/td-p/109524
and other mobile tools, I decided to give it a try with my 3', 150 lb workbench. I was flying by the seat of my pants instead of planning it out with sketches, dimensions, and such. I had to backtrack a couple of times, but the final results seemed to work.
I put casters on two hinged boards; I liked the idea of three casters for some reason.

Then I attached a 1/2" black iron pipe to a flange on each hinged board.

When the "levers" are pulled, the bench becomes mobile. I had to figure a way to keep the levers in the raised position, so I made a couple of "L" blocks. These blocks are loose, so I inserted a couple of lag screws just below the position of the blocks to keep them from sliding down while the workbench is moved. The pressure from the hinged boards keeps the pipes against the blocks, otherwise. I'll use these blocks on the 6' workbench too (when I get it built).
It wasn't easy, but I was able to back the car trailer down the "winding drive" that my wife wanted to give character to our entry -- sure would have been easier with a straight shot, but I like the curves, as well. Had to unload some early packing for our up-coming move (in several months) so I'd be prepared to help my son move his Vanagon from Raleigh to Charleston. It all worked out OK (emptying the trailer, that is; haven't gotten the Vanagon, yet).
We got the CO (Certificate of Occupancy), so I guess this is all legal. I'm really excited about possibility of getting some car parts in the workshop!