A slight divergence from the main theme of this thread, but the UASF bases in the UK also had a part to play in the 1960's mod / soul scene.
Quite a few GI's based over here would go out to local British soul clubs -- to enjoy a night out dancing but sometimes also to pester the live acts on there to let them get up on stage & perform themselves. Thus, we got Geno Washington, Sonny Childe and more.
In addition to military folk based here, US based acts would be signed up by the USO to tour to perform for troops based in Vietnam, Germany or the UK. I know quite a few US recording acts that came over here to play concerts in bases in Germany, Norfolk / Suffolk, Oxfordshire, etc. (Kenny Hamber being just one of these).
Taking just one base as my example, UPPER HEYFORD in Oxfordshire. This base (as did every other US one in the UK) had it's own shops, bowling alley & theatre. The US also ran the AFN radio stn in Europe as well as on-base radio stns (& newspapers). Most US personnel lived on base but in the case of Heyford, whole housing estates were built for officers & their families in local towns such as Brackley & Bicester. While lots of the time, the families would use the on-base facilities, they also frequented local shops, schools and pubs. Thus the opportunity was there to pal up with a Yank serviceman or two. If you did get to know any, they could take you on-base to go bowling with them or even to attend an on-base concert. The Norfolk bases such as Alconbury, Bentwaters, Mildenhall and Coltishall had more going on but Upper Heyford also had it's attractions. The theatre there; the SKYKING (where they showed movies & staged live shows) was quite small, so didn't accommodate huge numbers. But if the demand was there, a visiting act would have to do 2 shows on their visit.
No doubt, others have tales to tell about getting onto British USAF bases or getting hold of copies the US military newspapers printed over here. I know I have seen a few of these newspapers & they plugged upcoming live act visits quite extensively in order to keep locally based folk from getting too bored or homesick.