Yus! Exploring mainland is so much fun.
That church sounds hilarious and slightly creepy. Kind of sad it doesn't exist anymore. The wall tunnel you speak of. Shh. It's a secret.
Arton Rotaru vehicles handle at an even, steady pace. They make sightseeing worthwhile. Horseback is fun too.
Once spotted a huge castle filled with bouncy balls. Publicly accessible. Also came across a ufo crash with lots of bizarre things on site.
Avatars in the middle of nowhere... Sometimes, I'm in unpopulated mainland areas or at the bottom of the ocean sorting inventory, opening boxes, or decompressing in general. No idea what others are up to.
One aspect that never grows old is catching opposites, like a hobbit home next to a vampire castle. Neighbors with seemingly vast differences, residing harmoniously beside each other, always brings a smile to my face.
As Tari mentioned, prim buildings are lovely. For a virtual world to retain a sense of history, well, that's kind of a marvel.