Here's my take on all of the speculation over Lonesome Road (a scant 9 days from now).
There's most likely going to be Enclave present, or at least had passed through after the destruction of Navarro. Seeing as ED-E has his parts all over the place, I'm almost sure that Enclave Remnants will have had settled into the area, hiding behind whatever the experiment is that cut through the place in a manner similar to the BoS hiding in Hidden Valley using that sandstorm generator.
Ulysses himself may be former Enclave, or a member of some other pre-war community. It's quite likely he takes his name from these old Poseidon Energy posters:
The story of the "Odyssey" is the story of a Greek King, named Odysseus, who is on his 17-year journey home after an epic war (that Trojan War stuff). While the story is of a Greek king, his name in the Roman retelling? Ulysses.
It makes sense, maybe the Courier and Ulysses are from the Divide, and were sent to go scout the West and East. Ulysses went East into Legion territory, where he picked up his name. He and the Courier both chose the guise of a mailman, much in the same way Odysseus disguised himself as a beggar to find out the state of his house (or to Ulysses, America).
If the parallel is right, Ulysses is trying to get back home to America, or someplace with his idea of American values. He certainly hasn't found that in either the NCR or the Legion, or in New Vegas (he doesn't think much them). He may be headed to the Divide to find the last of his people.
If he doesn't find them in the Divide, he probably finds the missiles, and may try to arm them in an attempt to wipe the slate clean of the people who would try to replace his America with their faults (the mythical parallel of Odysseus slaying Penelope's suitors).
