The "redneck" way to do it with a portable unit is to have a 60a220v outlet in the garage, fabricate a "suicide" pigtail (male connectors on both ends), use that to plug the generator into your house circuit after you've wheeled the generator outside the garage door.

You'd have to focus on what breakers you throw and when, obviously.

Not advisable to run the AC or an electric oven, but if you have gas range and gas water heaters, it'll keep you going for as long as you can keep it fueled.