I'll be playing through FNV:UE soon on Hard difficulty, and with hardcoe mode on, and I read around a bit about recommended character levels for doing the FNV:UE DLC's, and also which order to do the DLC's in (so that they can all be challenging but not too hard or easy), and I've decided to do something like this:

Honest Hearts - Level 15
Dead Money - level 20
Old World Blues - level 25
Lonesome Road - level 30

But I've since read that you should play OWB before DM, because OWB apparently sets up characters that you meet in DM. So should I do OWB then DM, or DM then OWB?

Also, can you choose not to receive the Courier's Stash in FNV UE, and if so, should I choose to do that? I hear that Courier's Stash can make you overpowered at the beginning of the game. Although maybe Hard difficulty would cancel that out a bit?