Defense: Units deploying/operating direct from the DropShip with regular shifts running perimeter patrols. Units are likely to be close to secure for takeoff when not in use. Basically, correctly parked for the bay crew to secure within a few minutes of the takeoff order. Units normally carried in storage are parked outside or in local base facilities. Personnel are housed in the DropShip or nearby buildings, maybe temporary prefabs, depending on planetary/contract conditions.
Units likely to deploy: All
Fight: A rapid response force generally operating in friendly territory, but hours or a small number of days away from the main base/DropShip. This force has the benefit of basing in friendly territory and can choose favorable base locations, such as a large farm coop with AgroMech facilities, A local airport, etc. They can make use of facilities that may not be ideal to unit maintenance, but are much better than being out in the mud. The key conceptual difference between Fight and Scout is that Fight is in friendly territory and can afford to bring and deploy more equipment because the locals won't molotov it or steal it as soon as backs are turned. Movement from base to base is deliberate and requires some time, but is much quicker than packing everything into the DropShip.
Units likely to deploy: All types, but probably few/none of the slowest units. Limited numbers of conventional infantry. Conventional infantry require additional transport, supplies, etc. with limited payoff.
Scout: The Scout force moves with minimal footprint for both speed and concealment. Scout travels light, probably only deploying basing assets after a battle (or mechanical casualty). The entire logistical tail of the Scout force is probably a repair vehicle and a few transports. When given a choice between units, the choice should go to the fastest one as a default. So, choosing between the Paramour Mobile Repair Vehicle and the Wayland MFB would result in the selection of the Paramour pretty much every time, even though the MFB has more capability.
Units likely to deploy: Mechs, VTOLs, Aerospace, BA, and a small as practical support vehicle force (repair vehicle, plus supply trucks/APCs). Local base security is provided by BA, which may be mech mounted or carried by an additional APC. ASFs and VTOLs are based back at permanent facilities, but called in as needed.
Unit assignment:
Artillery
The question is whether Scout is "close" to the artillery. Artillery could easily be on the field or very close to Fight and still support Scout. Or, the range could be much longer and out of artillery range. Even Long Tom rounds only make it ~15 km. Additionally, most arty is slow, so you have the additional question of how fast the fight develops and whether artillery could position themselves to support. Mechborne artillery, like Nagas and Catapults, could easily accompany Scout and just work off map. Artillery would easily be available to other roles, including Training since there would be little reason for training to occur outside of friendly territory (though they may have some ammo replaced with training rounds, sucks to only have 1 ton of ammo...).
Heavy Combat Vehicles (Heavy/assualt weight wheeled/tracked)
Heavy vehicles are ideally suited to Defense where they should have prepared positions. Likewise, deploying heavy armor in an assault is perfectly reasonable for Fight. Heavy armor probably would not be with Fight outside of assault type missions due to the time it takes to travel and being better deployed as a perimeter guard at the main base. Conversely, Scout's mobility and concealment kind of precludes deploying heavy and slow units, especially Skaraborg Lance...
Medium and Light Vehicles (Non-VTOL, WiGE, etc.)
Deployed everywhere, particularly APCs. Non-combat vehicles, like cargo trucks, would probably prefer deploying within safe territory, but such units are also disposable and provide necessary capability.
Fast Vehicles (VTOLs, WiGE, and high speed Hover and wheeled)
Such vehicles are reasonably deployed with any role. Scout is likely to need/benefit from the presence of scout hover craft, fast APCs, and fast cargo carriers. Maxims, I'm looking at you. Likewise, VTOLs would benefit Scout, but their greater speed, ability to avoid terrain, and nominally higher maintenance needs (in reality, if not RAW) would argue for them to base in friendlier territory and assist Scout when called in. Basically, the designated reinforcements.
Conventional Infantry
Conventional infantry is best used for non-combat security at fixed installations and to combat other infantry. In other roles, their realistic support needs probably outweigh their combat contributions. For example, how much food would a foot platoon need compared to the entire lance and support staff of a mech lance? Add in medical support, transport needs and other concerns, and conventional infantry assets are probably best used in defensive action.
Battle Armor
Battle armor has higher mobility (most of the time) than conventional infantry and much higher combat effectiveness making their tradeoffs more situational. Higher maintenance needs for the battlesuits are offset by smaller unit size and inclusion of maintenance personnel and resources in the APCs.
/dissertation