Do you think I can handle a really long bike ride?

You should be able to do it 72 miles is not that far. 20-25 mile rides are an every day thing for me. You want to load up on carb's the day before the ride to get your glucose levels maxed out. Carry plenty of water and take some sandwiches with. I like to eat Good & Plenty on long rides it only contains sugar and carb's and no fat.