I would guess he’s going to Bedminster because the White House is not secure. It’s probably bugged. President Trump also used Bedminster during the last election. Probably a very secure location.
He has a hotel he setup as secret lair years ago right down the street
Bedminster aslo has better golfing. Sometimes the simplest explanation is the correct one.
Or he is having campaign meetings, which are easier outside the White House. Even though the President is not covered in the Hatch Act, most everyone else is.
Sometimes the real reason is boring.