[jmkupka]

Nobody on (A position):
Fly ball to left or center, BU comes into fair territory, outside the baseline, ahead of BR. Watches BR touch 1B, runs along with BR on the way to 2B, and if obvious BR will be continuing to 3B, cuts behind BR as BR approaches 2B; BU starts to move across infield, watching BR touch 2B and preparing in case BR decides to stop short & return to 2B.
If BR continues on, let her take you in to 3B; you're seeing BR, and the throw, and you are stopped and set to see the play at a 90° angle to the throw.

Fly ball to right field (if you're not going out for fair-foul or a trouble ball):
No problem with cutting into the inside of the baseline and button-hooking. This way the whole play is in front of you (BR touching all bases, ball position)