Go to a vintage event like Oldtimer GP
>race action all day
>huge variety in cars and eras, usually mixed with 1-2 modern series like Prototype cup or an anything goes amateur stuff
>races both on the circuit and full track
>sometimes parallel so you can watch 2 races at the same time from the old pits stand
>reasonable prices for entry and concession stands
>popular but never too crowded, access and parking was always chill
>full access to the massive paddock (obvious, but with this many competitors dragging vintage race cars around behind their van this is a great way to check out cars and have a chat)
Whatever you do, check the schedule ahead of time to plan your day around the races you want to see
Getting from the GP track to Ring spectator spots is a pain in the ass because traffic and lacking of parking, just bring bicycles

>tourist drive events
not an event, track's just open when there's no racing/industry days/trackdays