You could probably feed a hopper mouse now.

I don't follow the Munson plan because I feed rats, but a hopper mouse once a week, and adult mice every 10-14 days will be good for this guy.

I use the girth rule of thumb: The thickest part of the prey item (which is the hips) should be 1.0 to 1.5 times the widest girth of the corn snake.