What is you main line coming into your house? If it is a 100amp service a 12k generator will run your whole house. If you are looking for emergency use only there are a couple of ways to go.

If you are handy make up a smaller VITAL breaker box. IE freezers,refers,Beermiester(CLK) heat what ever.

Look at the capacity of the breakers in the box now for them add those up.
Drop a line from the main to the vital box. THIS WILL BE THE NORMAL SUPPLY. Have a second supply line coming into it from your generator EMERGENCY SUPPLY. Use a toggle type breaker(so that only one supply can be in the on position)

It sounds hard but any electricaly minded person should be able to do it in a few hours once the parts have been gathered.

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86 300SDL. 250,xxx on #14 Head. One eye always on temp gauge.. Cruising towards 300K