A home track is the speedway where a racer runs the weekly program every week and builds cumulative track points toward that track's championship, as opposed to the specials and touring dates scattered across the rest of the schedule.
IMCA’s rulebook does not make you declare a home track — attendance decides it. IMCA scores track standings on a “driver’s total cumulative points at that track,” so the track you keep showing up at is the championship you are chasing. What is written down is the attendance floor. IMCA requires a driver to run at least 50% of a track’s weekly sanctioned point events to be eligible for that track’s point fund, and the track must complete at least four programs before it can crown a champion. Tracks set the bar higher — Slinger Super Speedway requires membership plus 80% of points races for year-end awards. Your home track also decides where you start: IMCA lines heats by your average points over your three most recent weekly appearances there.
Picking a home track is picking a championship you can actually win, and splitting Saturdays across three tracks is how a racer ends up under the attendance minimum at all of them and eligible for nothing at any.