Rural tours are suddenly a trend on Hainan, with groups visiting real agrarian villages inland from Sanya's glitzy resorts.
The tours are usually advertised as "Nong Jia Le," which translates as "happy farmhouse." There's usually a quick walk around the village, then a lunch at a local farmhouse. Unfortunately, as of writing, there's no tours available in English, but if you're flexible, no one will stop you from joining a Chinese tour. The wealthy Chinese will generally speak English and adopt you, so it's a fun way to make friends and meet new people.
Ask at your hotel's concierge about 农家乐, or show them the website attached.