For long running routes it seems that the set of questions don't get renewed.
On one ride I did we were advised that the landmark in the question had been removed roughly 10 years previously.
The distances given only apply to the "shortest route" from the previous control and can vary wildly from what your GPS says, but then so can the route sheet...
As the purpose is proof of passage provided the question is sensible and written to be unambiguous and not mistakable for another possibility in a range of distance error I see no problem.
Questions like, In Village X how far is it as signed to the village Y at the junction.
Should work quite well as it should be fairly difficult to misidentify the signpost (unless it's been removed)
But not all route are going to give you such obvious points for routing.
Codes boards are another option, though they need some financial outlay and a need to have setup and cleaning run of the route.
Fine for Motorsports where the Set up, opening and closing cars are requirements for running the event, not so when organizers may need to ride the route the day before and after and hope no one's nicked them and have to carry the weight of them both times.
From playing with DIY routes round here, getting a decent route thanks to the valley roads being pretty busy and direct and the interesting roads being twisty, up out the way and with plenty of links down to the lower roads can be tricky without having to land a virtual control in the middle of nowhere, where the only option even for an info control would be "judging by the size of the discolouration of the car, what did the Kennoway gadgies burn out here"