The state of New Vegas will provision (pay for work, food, water, tools and materials) 400 labourers from Freeside to excavate the 3 derelict bunkers in Hidden Valley and repair them under the supervision of BOS scribes.
Afterwards, when these excavation efforts are complete, the workers will flatten the area surrounding the bunkers and construct sturdy stone walls in place of the current iron fencing surrounding Hidden Valley. These stonework walls will have entrances at the western exit near the correctional facility, the valley leading northeast towards black mountain, and southeast towards Helios 1 (leading through Scorpion Gulch), with a simple stone road network created between these facilities and Hidden Valley through the pathways connecting them.
After the Hidden Valley renovations, the previous NCR correctional facility will additionally be renovated by the New Vegas labour force and given over to the BOS as an above-ground military installation. Its insides cleaned out, and its walls reinforced with stone and gravel.
Additionally, New Vegas will set up an initiative program with the Brotherhood, where New Vegas will provide young orphans (if they want to) to the Brotherhood as potential recruits.
The area (visualised in the picture added to this post) around the Hidden Valley, Correctional facility, Helios 1 and black mountain will be seen as under BOS Military control. This does not extend to legal control, as the Mojave chapter of the BOS and its extensions will be seen as citizens of New Vegas and thus be under its legal jurisdiction and protection. The brotherhood in this context, will be seen within the New Vegas government as a Highly skilled Militia and given rights as an organization within the New Vegas government to have it's own separate command structure and autonomy to act militarily without permission from the state of New Vegas as long as it does not threaten relations between New Vegas and other states. If BOS leadership still deems it necessary, a request can be made to New Vegas and be deliberated over for the betterment of everyone involved. The BOS acting elder will also become part of the leading council controlling New Vegas and answer to no one except the current head of the NV state.
In exchange:
The Brotherhood of Steel will provide scribes who will work to both maintain the Hoover Dam, as well as repair and replace damages done to it. A garrison force consisting of Brotherhood paladins will help protect the Hoover Dam, and automated laser security turrets will be provided and hooked up to the Dam's energy network.
The Brotherhood of Steel will accept one of the renovated bunkers to be given control over to New Vegas directly, to be partially shared in usage between the Brotherhood of Steel and New Vegas for purposes of collaborative projects.
Together with the Brotherhood Initiative program provided by New Vegas, the BOS will allow students nominated by New Vegas for a sponsored education to participate in BOS schooling, so that sponsored students can work on the same educational level as a Brotherhood scribe when finishing their education. The BOS are allowed to restrict students from topics if they involve the study of technology related to sensitive BOS-kept secrets, if reasonable (we are a reasonable man about students handling mini-nukes). New Vegas will provide resources to the BOS to compensate for keeping said students.
Within the partially shared bunker, the BOS will help work on a weather alteration program for large-scale manipulation of the rainfall within the Mojave using the technology from the Hidden Valley DERVISH camouflage system and donated weather manipulation systems provided by New Vegas (the Big MT stuff) and reverse engineering of additional projects (such as the Sierra Madre Auto-doc and Deathclaw taming)