[dcb]

but you are suggesting it is "sensible" to carry a generator with you everywhere you go, and to rig up heat to your air cooled generator apparently, just in case you fail to plan or think. That is akin to towing a scooter in case your car runs out of gas. It will hurt your mpge during the other 99.999999% of the time when you operated your heavy equipment correctly.

The sensible thing is to not run out of gas in the first place. The next sensible thing is to be efficient about extending your range. Series here is only good for "emergencies", whereas a long hiway trip can be handled most efficiently by a parallel setup. You can plan, even desire, to use your range extender if it is efficient and something you can unbolt when not needed. If parallel has gears it can offset battery usage around town as well.

Carrying it around "just in case" is just bad planning, not sensible. It will not improve overall mpg, because you are adding it to a BEV in this case, you will go from "infinity" mpg to something less than infinity mpg if only in evaporation. Use your head...