beyond fueling you have found the 2nd most important element of long distance cycling: bike fit. If you could find a local professional bike fitter I would invest that route.
regarding numb toes, could be several things: driving from 12 to 5 with you toes down and not dropping heals, shoes are too tight cutting off blood flow, curling toes due to shoes being too loose causing blood flow issues ... lots of issues too tough to identify from here.

You'll find this and other fit issues that show up on rides longer than 2 hours. Other things likely to show up = hand/wrist aches, upper back aches, butt hurts, etc ... most can be traced to fit issues, rider position, or just lack of mileage identifying muscles that need conditioning.

Heed the advice given and I am sure you can finish ... doubt you'll need the headlight