Hook Up Gas Furnace Portable Generator

I know the most optimal solution is using a transfer switch.
Hook up gas furnace portable generator. This set up doesn t require the breaker to be turned off. I am not looking at. The furnace is wired into the circuit breaker. If you use a portable generator.
Then should i need to hook up to the generator for any long term power outage i can unplug the furnace and plug it into a heavy duty cord or permanent wiring to my generator outside about a 15 run to the outside. The easiest and simplest way to avoid hooking up my generator to the house panel would be to put an outlet on the furnace and then run a heavy guage wired plug to that outlet. Make up an extension cord to go from the generator to the twist lock outlet on the outside of the house. This is a simple way to run your gas furnace off a portable generator.
Get a 2000w inverter generator which as far as i understand would give much cleaner power and better gas consumption but with a more limited output that will reduce the number of devices i can power. When the power is out you simply disconnect the furnace from the outlet and connect it to a extension cord. Take the unit outside that is a minimum of 10 feet away from openings. Hookup the generator to internal equipment using one of the following methods.
Run many extension cords from external to hook up to electrical devices. When the power goes out turn off your main breaker turn on your 60 amp backfeed breaker turn off all the breakers you don t want to run leave on your furnace refrigerators freezer and tv and maybe a lamp or two. You run this cord outside to your generator start the generator and once it is sufficiently running you plug the furnace in and use it like you normally would go to the thermostat and crank up the heat. Run a single gene code from a generator machine and hookup many appliances.
The materials cost about 15. Can a portable generator run a furnace. Just remember most high efficient gas units need 100 ground. You will increase higher chance of burning up a control board.