Bear in mind that if the helmet did its job most people would tell you that they did not even hit their head, or did not hit their head that hard. And the thin shells on most helmets now tend to hide any dents in the foam. But if you can see marks on the shell or measure any foam crush at all, replace the helmet.

Its entirely possible the bike is good and safe to ride with a bit of air in the tires and shocks/forks - this would heavily depend on the climate in the garage it was stored in and condition it was in before being hung up. Presuming the bike looks in good condition with little or no surface rust, the following are the things that might need attention apart from what a regular service would entail (regular service is things like chain clean and lube,tuning brake check etc.

Bicycles are a fun and increasingly popular way to explore destinations. But whether you travel with your own bicycle or rent a bike from an on-demand kiosk or local vendor, it’s important to know and follow the local biking rules before hitting the road.