Maybe you should ask and see if the Brotherhood knows anything about that area before committing."
I think this is where the Brotherhood realizes Lily's space assets. I can see them using it to check out the NCR and various places around the US and the world.
With access to Lily's satellites, their slowly rebuilding airforce, and their slowly growing military power they can start to expand their immediate influence out to a hundred miles. Maybe out to Boston for delayed support, which will likely stop the current decay of the Commonwealth Minutemen. With Lily, maybe, unearthing the Institute before she leaves.
Yeah, once the West Coast Brotherhood reaches out, the NCR is going to be absolutely horrified. Mr House is going to try to order a new body from Lily, but I doubt she is going to be willing to go out there, the Brotherhood will likely be more willing for a tech exchange.
A Brotherhood that is growing, their technology is advancing with the support of an advanced pre-war scientist, have an increasing amount of their local area under their supervision/control, and some of the local towns can even produce increasingly advanced tech like fusion cores/plasma weapons/advanced T-60 power armor in increasing amounts. Even their life science is advancing, able to clone and replace limbs (not mentioning cloning new bodies and doing brain transplants if needed).
Yeah, if the West Coast Brotherhood shows up in New Vegas the NCR will shit bricks. I think the Vegas Brotherhood may shit bricks for different reasons although.
Edit: I'm kinda surprised the Brotherhood isn't using its increasingly powerful and mobile force to start smashing down on raider camps. Hell, use one of their birds and some cheap mortars, they could put a decent dent into various raider camps. Worse if they setup some light defenses with their Power Armor. Use the mortars to smash the camps and force the raiders to attack the Brotherhood's fortified mortar emplacement. With the mortars continuing to smash the attacking raiders, while their heavily armed Power Armor in fortified positions rebuffs the attacks.