It's a resistor style series drive system, so in that respect it is about as simple as you can get. Brake (yep, one) should be on the shaft connecting the motor to the rear end, it's a disc setup. What would I give? No more than $1000, that's the top dollar "just gotta have it" price IMO. I'd be comfy around $750, and increasingly more happy the smaller the numbers get.
I recently sold my HD gasser and had a heck of a time finding interested folks. There is a market for them, but it seems pretty small in my area.