So I was going nuts reading that OXCE had a craft range indicator that I never could see for some reason. Searching just turned up the fact that it was there and not how to activate it or anything - just that it was 'always enabled'.
Well, for anyone else having the same problem, it's tied to the Options -> Geoscape -> Globe Details -> Radars button. This makes a lot of sense, but for whatever reason I had failed to turn that on in my fresh install of X-COM Files and it had gone unnoticed because I have yet to make it to radars anyway.
a little SEO stuffing for anyone else in my shoes: max range indicator, craft range indicator, interceptor range indicator