Many girls have problems with eating and drinking on the bike. For a one day challenge it doesn’t matter if your body doesn’t recovered the next day, but when you are doing a Roadtrip such as this, it is really important to get your recovery right. We have a rule in stage races: Your recovery time starts on the bike, and this is exactly the same for the roadtrip. Drink at least 1 bottle an hour and eat 1 bar/banana or something you. Try to do this during your training rides as well, so you get used to it. During the Roadtrip there will be lunch stops, so that will be a good moment to eat and recover, but between these stops it is good to eat on the bike as well.
I have heard many stories about gels, but personally I prefer to use them only in the final stages, during the race I always eat bars.