My advise would be, no bypass that has to be manually switched. Do you know yet what your indoor or secondary heat will be? Do you have natural gas in the area? here are a couple of pro's and cons of gas vs. oil, with gas you are typically locked into doing buisiness with one company and cannot shop for a better price with another company, but they are quieter,more efficient, no need for chimney (direct vent ) instant heat, low volume of water to keep hot and wall hung to keep it out of the middle of the floor. Oil can be purchased from any oil dealer allowing you to shop on price and easier to service, both in my opinion should be direct vent keeping any chimney open for an indoor wood fired cookstove. Both should be plumbed primary secondary piping to allow for any future additions to the system, solar thermal, hot tub, pool etc. and keep the manifold on a wall away from your boiler for easy service in the future. Both can then be switched automatically to fossil fuel when the incoming water temp from the wood boiler drops from lack of wood with a simple aquastat wired to B1 on the gas or oil boiler. You will spend some extra cash up front but if you start out right then it will be very easy to expand the system in the future. Very nice looking home, good luck, keep in touch.