I'm about to go into Lonesome Road for the first time. My Courier is level 31, got good skills etc.

I am aware of how difficult many find LR so wondering what are some things I can do to prepare myself before going into it?

If you go to the Courier's Mile (which is optional) you're going to want Rad-X and Rad-Away. And probably Stealth Boys.

A good scoped weapon is helpful, as there are many opportunities for long-distance sniping.