Problem solved for $12. and an hours time. My local hardware store was running a special; heat only thermostats for $5.99 . I used one to control the coal boiler, set that at 65 degrees. Used another one to control the furnace fan, set that at 65 degrees. The third one (original one) is set at 55 and will turn on the propane furnace as a backup in case I'm gone and the coal fire goes out. (as long as I remember to turn the gas back on, it really felt great to shut off that valve ) I could have used a 2 stage t-stat or wired up switches and relays, but this way works best for me, each system has it's own manual control so I can play with the settings pretty easily. I let the fan run after the boiler shuts down to blow off the stored heat into the house, that's "free" heat.
I might have to set them at different temps, we'll see.