Rubber can degenerate in storage, so you might need to replace the brake pads (dig a fingernail into them and see if they still feel resilient). These are cheap and easy to replace, so you may want to just do it anyway. Check the sidewalls of the tires for hairline cracking. If the tires are too far gone, they may not be able to hold the rated pressure, and that would slow you down.
Some parts are especially vulnerable to rust in storage. Look at the chain. Put on some plastic gloves and go along its length, flexing the links to find any that may be frozen. Give it a good drenching with chain lube. The brake and shifting cables have a steel cable core that runs through a plastic-coated cable housing. Sometimes the inner core gets rusty and makes the cable action balky. See if the brake levers and shifter seem to function smoothly. Replacing the cables is not a big deal if need be.
Those are the main things that I’ve seen crap out in storage.
Good Luck!!