If you are going to 'co-generate' heat, a small recirculating pump could be used to pre-heat the engine from the hot-water tank.  Another way to preheat gently would be to make a small tube-in-shell heat exchanger and use propane or some other small heater and heat the combustion area for easier starting. Pre-heating engines also reduce wear as engines need to get to operating temperature for best wear charactistics.  A thermostat should be used in all engines and it should be of the proper temperature range to assure proper operation.

In aircraft, oil is drained at night and heated before cranking the engine in really cold weather. Fires are even built inside the cowlings to heat the cylinders for starting. I'm sure not many have the testocular fortitude to build a fire under a gasoline engine - when it is the only way out of the 'bush'.

Ether can be used to help starting in cold weather.  It can also cause engine damage and/or hard kick-backs in small diesels.  A SMALL amount of gasoline held on a rag in the intake or put on the air-filter will do similar things with less chance of damage.

For noise and vibration reduction I am considering building a 'floating' generator and moor it in a small pond.  A light dose of oil on the surface would keep the oil from evaporating and small dock-lines would keep it centered.  The only connections would be the wiring, waterhoses, fuel lines and oil-lines to a by-pass and conventional oil-filter.  The exhaust would supported and have a flex-coupling to the 'boat' but not the shed. This would isolate the radiator from vibration problems. Vibration eats radiators on thumpers. It would also have all the maintenance pieces off the engine and where it coould be easily serviced.  Ease of service usually means more consistant and better service.