I've always enjoyed seeing other people's gardens and landscaping.
You can get great ideas for your own place and get to spend the day enjoying the results of someone else's labor!
Details can be found here:
Last year Gretchen and I met, and rode together to each place we decided we wanted to see and skipped the others.
We stopped and had lunch along the way. It was a truly enjoyable day.
This year's tour is bigger and covers a lot more ground so some hard choices may need to be made in order to see everything you want to see. :(