I'm not sure I can help much on this. When I was actively flying them, we had conus bases at COS, RND, ADW, BLV, MXF, and FFO. MXF and FFO were flights under the Sq at ADW. COS and RND were flights under the Sq at BLV. All under the BLV wing. Oconus, there was ETAR and RJTY, as well as MPPA. At least one staff agency (AFFSA) flew them as well out of ADW then OKC. Schoolhouse was Simuflite at DFW and jets at BIX. There were about 86 jets divided up between the locations. We rotated covering west coast and central, south, America and Caribbean. We all rotated iron swaps to desert and exchanging tails with oconus birds for corrosion control and other reasons. We rotated covering 24/7/365 bravo or alpha alert aeromed evac mission (2 units on, 4 off, repeat every three weeks). Near permanent deployment to PSAB.
So much for history. As I understand it, only COS, BLV, and ADW remain. Schoolhouse at BLV. AFFSA lost theirs as well, and many went to a few guard units as those units transitioned to other aircraft. Many tails went to AMARG. I don't know if OCONUS units still exist.
Now, if the mission is the same, each base offers up x tails for missions daily. A central scheduling agency apportions the missions to the units. A mission supports and lifts whoever can get approved. Could be a courier 2-striper, important cargo, or a 4 star general or a senior SES. Or, BLUE BARKs, aeromed evac, human organs, or you go rescue some other lift who's jet broke somewhere, etc. The important thing is to be on time and fulfill your frag.
Each unit also likely flies 1-3 training lines daily. Most missions (60%) are 2-3 legs done in a day. Others include an RON, or a few per month are multi-day trips. Most training lines are 2-3 hr transition style locals at nearby fields, or sometimes out n backs. Occasionally, a unit will take on the enormous challenge of getting a long oconus trip approved to alaska, canada, south america, or a European jaunt (the trip planning is easy, getting it approved is ridiculously difficult).
Crews normally showed 3 hrs prior for upgrade sorties, 2 hrs prior for all other missions, except alerts. Both pilots go over mission and brief, then one pilot files, etc and the other preflights. An experienced crew could be airborne (legally) in less than 10 minutes from showing at the aircraft.
Lears are fun to fly, can kill you really badly in only a couple ways, and are pretty forgiving, so are excellent airmanship builders. Since you often service the jet yourself, and even make certain repairs yourself, the units expect a very, very, very high level of knowledge about the aircraft and systems, how they inter-relate, and how various malfunctions can affect the jet (think EPs for which there is no checklist). But it's not a difficult jet to learn or operate well.
That's what I recall at the moment. If I think of anything else after my ginko-biloba I'll edit the post.