Whistlenut/Rob: you both bring up a good point regarding the creosote issue. I've heard that adding some sort of water storage tank will ensure hotter, more complete burns and lessen that issue. I'm assuming an 80 gal superstore DHW tank would make a decent heat sink, even if it means hotter temps than typically required for DHW, maybe keeping the hotwater setting low and adding a buffer tank inline with the hotwater "out" line could make this scheme doable?
What about a strategy that uses the oil burner more in the warmer spring/fall days when there's more frequent on-off cycles of short duration and saving the wood/coal boiler for the colder days/weeks to get the more intense burns? That seems like it would nearly eliminate the idling issue and require less dumping of excess heat. It would require more oil usage, but the lion's share would still be replaced by the alternative energy boiler. Longer return on investment, but much better maintenance-wise. Thoughts?
Rob, thanks for providing that forest management link; I'd heard at least 10 acres was needed but 15-20 makes more sense having read through that. I don't have nearly that much, but the property abuts 50 acres of town/state land with lots of blow-downs, I may need to check that out some more and see what permissions are required. I figured wood wouldn't provide most of the btu's, just wanted the flexibility to burn it if for whatever reason coal prices jumped (due to cost of coal itself or cost of transport several hundred miles from PA). Please keep the comments coming, they're very much appreciated.