The National Trust is unique in that a membership provides access to carparks, houses, cultural sites, and sites of natural beauty. It's worth the membership just to park in Cornwall really. The equivalent in the USA would be a membership to US National Parks or State Parks. I enjoy going to Tyntesfield and Stourhead as they are most local to me in Somerset, I recently went to Longshaw near Sheffield and it was a lovely day out walking on the Peaks.
