I've encountered the same issue after about 10-12 hours into the DLC. Whenever I approach the Wilderness Exploitation Area and attempt to either manually save or when the game attempts to auto save, the game crashes. I'm therefore unable to progress the DLC to its conclusion, thus I consider this to be a game-breaking bug that has rendered the DLC unplayable. This was extremely upsetting as I had waited to play this DLC until this past weekend, which were my first days off after working 15 days straight.
As for the suggestion to start a new playthrough to create a different save file, that is not only a terrible suggestion to redo hours of work, but I've also read numerous reports from players on reddit and other social media who have in fact done this already only to encounter the same issue again with the game constantly crashing on them.
I strongly encourage Obsidian to make identifying and fixing this bug a PRIORITY. This game has earned a well-deserved reputation for quality with this amazing RPG entry, up to this point. It would be very disappointing if that reputation was tainted by this issue due to a lackadaisical response and/or untimely resolution. In the meanwhile, I've submitted a refund request to Microsoft for this DLC. I paid for a product with a reasonable expectation that it would work, and this DLC is currently unplayable for me. If and when this issue is fixed, I'll consider repurchasing it. I suggest other players reading this do the same. The more refunds requested from MS, the more likely there will be a potential SLA breach that will motivate Obsidian to address this issue quickly and satisfactorily (without forcing players to delete save files and redo hours of content).