I was under the impression that only an Initial Rating or a Rating Renewal covered the requirements for an AFR, an Endorsement does not anymore.
I believe especially for a PPL holder an AFR shouldn't be a test of sorts but more a competency refresher. Give them a 1 on 1 Q and A on procedures, weather, the aircraft and airspace/regs changes. You will get a feel for where they are at. If they don't understand something it is a great time to ask. Better to ask now than bang into CTA without a clearance!
As for the flight I use a short Nav, that covers CTA, a Non-controlled Aerodrome, GAAP entry and exit, few touch and go's, prehaps a glide approach and on the way back .2 of IF with some steep turns and a PFL. Usually takes 1.3-1.6hrs
Gives you a pretty good idea where they are at, and can dust off skills they haven't used in years!