Hey, congrats on your first Fondo! Hope you had fun with it 
On the downhills I found I could just coast with the pack most of the time, it seemed to really bunch up after the bottom of the hill so I was never really stuck trying to catch up or anything, mostly just making sure to stay safe in the pack the let myself roll up the group as they slowed down at the bottom.
I generally prefer to take my fuel in liquid form, the Beta fuel is a pretty simple mix but annoyingly expensive, I only use it for hard rides and races. There is a thread here on making your own so I will probably give that a try once my current stock runs out.
I never stopped on the ride, it costs too much time if you are trying to go fast. Never needed to pee stop but if you are taking longer on the ride or doing the Forte you might have to make a stop.