I changed my L3 to assist. Assist has you target what your target is targeting. Good for healing the target of a boss or selecting the mob that the tank is currently targeting.
R3 you can change to macro #99 and use something like the following sprint macro.


A simple Sprint macro is just
/ac Sprint

A more complex Sprint macro is

/ac sprint <t>
/mount "Main Mounts name"
/ac Sprint