Line drive single indicates a short hit, 1B covers the bag 2b is cutoff unless RF
has strong enough arm from short RF. I had a RF charge a sinking liner yesterday,
gloved it on 1-hop and threw out the batter at 1B. If there was a girl on 2B, 1b easily had time to
turn and get her at the plate.
A deep drive to RF (double) the throw will go to 2B anyway,
or 2B is the cutoff on runner advancing to home. Have never
used corners for cutoff
Our 1B is always the cutoff, regardless of where the ball is hit. The only exception would be if the ball you describe is shallow enough to have a play at 1B. If so, the 1B will stay there to see where the throw is going, then move to cut-off.
We use the pitcher as the infield cutoff and the F4 as the outfield cutoff. If F3 cuts the ball then batter runner is free to round and retreat with no penalty. If F3 stays home you have the opportunity to throw the runner out on a cut where the runner rounds and tries to retreat to 1B.
F3 staying on the bag and looking to receive the throw from RF will tend to make the batter/runner run through the bag instead of rounding (especially with 2 outs) which can significantly reduce the chance they will be able to advance to 2B if a play is made at home.
Let's not lose sight of the fact that OP, states "line drive single to RF"
A well hit ball down the line is rarely a single. My vision of a single to RF
is a short line drive over 2B head or in the hole, not a shot down the line.
Lets keep proper perspective of OP
What age group? Prior to HS, I use 2nd base as the cut. Or even in HS, if they are beginners, my cuts are 2nd base and SS. It can get too confusing if sometimes it is the 1st baseman and sometimes it's the 2nd baseman.
Since you said it's a single I would not have 1st base cover the bag. She would line up for a cut-off to the plate. Whether or not we need that cut-off depends on how deep the line drive was hit and the arm of our RF'er.
2nd base is our cut-off only if the ball gets by the RF'er. Hopefully CF is backing her up.
We have our pitcher running between 3rd and home and ready to back up a play to either one. She is not a cut-off for us in this play.