For F:NV, I designed (but did not write the dialogue for) all of the companions and companion arcs. I did all of the system design and balancing. I wrote all of the high level RDCs (Region Design Constraints) that area designers used to write their ADDs (Area Design Docs). I wrote the dialogues for Arcade Gannon, Chief Hanlon, and President Kimball.
For Honest Hearts, I was also the project director. I wrote the story, designed and tuned most of the gear, designed all of the main characters (the Happy Trails caravan, Ricky, Joshua Graham, Daniel, Follows-Chalk, Waking Cloud, and the Survivalist) and wrote Joshua Graham and Daniel (Ricky, Stella, and the Survivalist were written by John Gonzalez; Jed Masterson, Follows-Chalk, and Waking Cloud were written by Travis Stout).
For Gun Runners' Arsenal, I did all of the design except for scripting, which was done by Jorge Salgado and Jeff Husges.
On the other DLCs, all I did was weapon tuning.