The roundhead Regal lathes are a good home shop lathe in that they do not have too big a footprint and are very user friendly. A roundhead Regal lathe such as you have described, with taper attachment and long-taper spindle nose (as opposed to the threaded spindle nose) is a very salable lathe in my opinion. The fact the lathe has the mechanical clutch in working order is also a big plus. It cushions the starting of the spindle, and also is a bit more efficient in terms of electricity consumption (motor already spinning when clutch is engaged, no repeated starts requiring heavy inrush current to the motor).
As for price, anywhere from $700 - $1500 seems like the ballpark. It would be a shame to scrap this lathe. If it is all intact and working, albeit minus the thread dial gear, I would make a good effort to try to sell the lathe as a running unit. Parting out is a dicey game, with having to list the parts and wait for people to make inquiries, make offers, then pack/ship parts. These Roundhead Regal lathes seem to be listed for some high-dollar prices on ebay, and in our local Craigslist, some ancient lathes like Reed, or Seneca Falls, as well as beat-to-hell Southbends are listed for upwards of $1000. They are not making anymore Roundhead Regal lathes, so if you can avoid scrapping the lathe and sell it to someone who knows what they are getting, that would be the ideal situation.
I've got a 13" x 42" Roundhead Regal built in 1943. Fully tooled with taper attachment, steady and follower rests, 3 & 4 jaw chucks, face plate, dog (catch) plate, lantern toolpost and a few toolholders, chip pan and coolant pump. Some wear on the bedways, and the threaded spindle nose. No clutch, just the belt drive off the motor. I paid 700 bucks for my Roundhead Regal and that was a good 8 years ago, and it was part of an estate liquidation. I've seen similar Roundhead Regal lathes listed on Craigslist or sold by used tool stores for 1200-1500 bucks. This is in an area of NY State that is hardly a machine tool desert. I would think that your being in Maryland, you should have no problem in selling the lathe as a complete running unit.