The Middle - Timekeeping and Travelling Marshals
When you get the routebook, it will be annotated with the time the fictitious competitor number 0 arrives at most of the sections, rest stops, start and finish. This time is known as 'standard time'. If you're number is say, 63, then your scheduled time will be standard time plus 63 minutes.
Two reasons to have timekeeping is to make sure the trial runs and finishes on time, and to make sure there aren't great groups of competitors causing delays.
There are penalties for being late and the later you are, the lesser an award. These are detailed in the SSR (Standing Supplementary Regulations) that every member is issued with. So, for example, last time I checked, if you're otherwise on a 'gold', if you're more than 10 minutes late a Time Control (Time Controls are clearly marked as Time Controls in the routebook), then you're liable to get dropped to a silver. Similarly, penalties might apply if you're early at a time control. Sometimes the routecard might say 'no penalty for early arrival' for a time control. It might say 'ETA 0245", where ETA = Earliest Time of Arrival, for a time control that has a standard time of arrival of 0330. So if you're number 30, your scheduled time of arrival at this control will be 0400, but you can arrive between 0315 and 0400 and avoid penalty, because there is an ETA allowance of 45 minutes. There may be no ETAs in the routebook.
Having said all that, there are delays - for example a queue at a particularly difficult section - so the club has been flexible in the past. Travelling Marshals scattered throughout the entry record delays at the sections. The same people are there to help you, so if you're parked in a layby somewhere on the route, a competitor with an orange armband may stop to check you're OK. Having said that, don't rely on them to have a stock of spare inner inner tubes/spark plugs/tools/bulbs/fuses etc. You need to carry your own spares and tools to fit them just as you would with, say a day's trail riding.
The timekeeping regulations seem complicated, but there's no need to worry and no need to rush.
I just try to stay on time.