I'll just move into the kitchen

Depending on the layout of the house, it might actually reduce the efficiency of a central air system if you close off vents or rooms.
Generally you should just leave the system to work as normal, and assume that's optimal.

My backroom/addition/laundry room I keep the thermostat colder in the winter. No need to keep my freezer and dryer warmer.

We still have base boards in our apartment and each room is heated individually