A National Trust Card is a Cornish resident's new best friend! As well as supporting the organisation and gaining access to many of the houses and museums across the county, I know plenty of people who reckon their National Trust membership is totally worth it just for the car parks.
It's £6 a month for an adult membership and many of the parking destinations cost this for a one-off, so if you go at least once a month it becomes totally worth it. I think I use mine on average once a week, and my go-to places are Bosveal, Gwithian, Chapel Porth, Kynance Cove, Lizard Point and Trelissick. Having the card also encourages me to explore new places in order to 'make the most of it' and branch out beyond my usual routine.
A few places (Glendurgan and Trelissick are my closest) unfortunately don't allow dogs in their gardens so I haven't been in to the formal areas, but the car parks lead on to lovely walks around the surrounding countryside and you can visit the cafe afterwards.
There are almost too many to list, but I will be gradually making my way through them over the coming months - I'd love to hear your recommendations too.