Marshalls moving to Mildenhall idea always sounded very odd to me, considering active AMC/USAFE/AFSOC base and a civil MRO and flight ops company moving in and around its space.
In theory the commonality of the C-130 support, maintenance and flight operations complement each other from both organisations, as well as Marshalls expertise on AAR could be an asset to the USAF but more on the HC-130/MC-130 front
One time in the 80s/90s, the C-20 fleet from Ramstein used to pop into Marshalls for wash and clean up and probably some minor maintenance work.
On the minus side, there's security issues, unfortunately its not similar to say civil airport in USA such as Portland IAP, Klamath Falls, Dallas FW, Phoenix Sky Harbor or Harrisburg IAP, that have ANG/AFRC units operating one side of the airfield with the run of the mill F-16/F-15/C-130/KC-135 in a small secure area but we're talking a fully active 24/7 base which is the link and support in and between the major commands and theaters of operation, so it would be slightly difficult to integrate Marshalls within Mildenhall's infrastructure.
Not sure about Alconbury, again an active base not flying but very active in support of JAC Molesworth, Fairford, Menwith Hill, Croughton, Sola/Stavanger and any other facilities. Then again one side of the facility is a semi industrial estate so maybe the use of the runways and old hangars, and re open the control tower, Marshalls could in theory move there.
Wyton wouldnt be much of a problem, they operated heavy multi engine for years, and up to 90s, operated 51 Sqn with Nimrod R.1. Runway probably handle the odd 747 such as the BA 747-400 going in there on/off in the 90s. Advantageous to the Lyneham residents for maintenance support as most of the Herks can be seen flying over this area, for exercises or general ash and trash hauls across the globe.
Looking at the pan here, when I do go flying in my Robbo, theres mainly Herks, occasional twin props narrow regional and narrowbodies, lots of corporate a/c, Netjets, Marshall Executive Aviation and private owners alike then there's the flying clubs and my flight school plus others. So on average, 20-30 a/c on the ramp and potentially Wyton could handle it.
However there's an assumption that Marshalls will move when they feel like moving and sure as anything won't move with pressure from local government.. What makes and says what goes on in my hometown with those being the university and Marshalls and with the former, the science park(s).