It's not too bad of a situation. Luckily, the two events are different enough that you are going to call on different physical abilities.
During the Saturday road race, make sure you stay hydrated and nourished throughout the race. Gels, energy drink, whatever you want to get those simple carbs. In the immediate aftermath of the race, try to get 50-80 grams of simple carbs into you. Recovery drinks are fine, orange juice, chocolate milk, even soda will work. Several hours later, have a larger meal, with a good amount of carbs. And take it easy. Drink tons of water throughout the rest of day to rehydrate and get some good sleep.