Bare with me on this...the entire Lonesome Road plot revolves around You (the Courier) having some history with Ulysses. The "very superstitious...writing on the wall" at the canyon wreckage beckons the Player to "go home now Courier 6", suggesting that the Courier was originally from the Divide (OR Ulysses is remarking that the Divide is where the Courier BELONGS...as they say, home is where the heart is). This is reinforced when Ulysses comments that "The Courier knows the way", therefore the Courier must have travelled there (or from) some point in the past, this is likely because the nature of a courier is to travel.
Ulysses has two agendas. Firstly, You. Secondly, the Old World. Wheather You and his plans for the Old World are connected, remains hidden. Ulysses wants the courier at the Divide to "See what happened", indicating the Courier left the Divide after a major event that You (the courier) possibly (likely) played a hand in but left before seeing the consequences of events.
One final food for thought...Ulysses: "Got a message for [her/him], like the message [she/he] had for me", "People are like couriers...Sometimes don't even know the message they bring". You done something thet brought about consequences that were unforseen/unintended that affected Ulysses (what happened at the Divide), and now he's returning the favor.
Whatever the case, it is my medical diagnosis that Ulysses is obviously suffering from a case of "Old World Blues" that can only be treated with a healthy dose of "New World Hope"...the world You create at the end of New Vegas...
So, wadaya think? and I mad?