I feel like an idiot for asking, but where do I go to view my uploaded data from the gas and the trip cubby. I need to have them printed for tax preparation.

Use Export to email your data to yourself.

Online Sync is not accessible right now via browser. The only way to manipulate Online Sync data or recover from data loss is through the Sync button. Honestly, it's complex in its simplicity <---- that sounds like some silly proverb but it's true.