How about considering an air traffic controller to assist? Familiarity with r/t procedures, phraseology, and ATC procedures in general (albeit depending where you are). Quite a few have PPL and even CPL experience - and I'm sure they could manage a check list.
So, let's get this right. One pilot incap, other pilot flying by him(her)self. When it comes to do a checklist he keys the microphone, negotiates with ATC asking if they could assist by reading his checklist out to him(her). ATC, bemused, agree and ask for him(her) to read the checklist out over the RT so that the controller can write it down. Pilot obliges, including giving all the standard responses so that the ATCer gets the full picture.
Then, and only then, can the pilot ask the controller for the 'Approach Checklist', which the Air Traffic Controller now obliges with, AND what's more checks that the pilot gives the correct responses (because the pilot told him/her what they were earlier!)
A major advance in aviation safety when flying single crew I would say.
Would love to hear the 'Landing Checklist' at 4nm........
PP