Appreciate the help. I like Tom Sawyers approach definitely over complicated. I had a plumber check it out and he agreed the temp down there is very comfortable. He said a 16 ft run on the long wall where the windows are will be plenty. I was going back and forth between just putting a pellet stove or doing the baseboard. I'm just waiting on the estimate.
I estimated the parts $150 for baseboards, $130 for zone valve, $75 for pex pipe, $50 for thermostat and wire run and then any little misc copper Ts to tie it in. It'll be interesting what the labor amounts to rough it, drain the boiler and tie it in to existing system. The estimate I get will decide if end up abandoning ship and throwing in the stove or rough the pex myself and tie it in down the road.