I usually rely on AF in dark rides - set to spot focus point and AF-S, I've rarely encountered a scene that a DSLR-type camera was incapable of focusing on at least some point in the composition. Usually I look for any light or glint of light on the subject to be focused and that does the trick.
When and if I do need to manually focus, I will usually focus strictly off the center spot focus point - I find manual focusing quite a bit easier with my mirrorless camera compared to my DSLR in dark rides because of the mirrorless camera's focus peaking system that lights up the in-focus edges of the subject, and because I usually use it with old, fully geared & mechanical focus rings that give good feel and feedback when focusing, compared to fly-by-wire focus rings on many newer lenses.