I dont see the point of this as you dont have any resource other than visually estimating how far off route are you. In that case, wouldnt turning towards your reference or making a visual correction would sufice?
Im a low tech flyer myself as I navigate with nothing but a mag compass (questinable acquracy as well) and a navigation chart. I limit myself to following things (railroads, roads, powerlines etc) no farther than 5nm depending on the situation. Works out pretty well for me.
I guess I simply dont see how what you are asking for can actually become practical in real un-aided VFR navigation.