Does anyone know where I can find, preferably on the internet, a good map of the Hang Dong and Ban Wan area? I want to check out the furniture stores and like to have a decent map when driving in a new area. My Chiang Mai maps don't cover that area, and my northern Thailand maps have no detail at all.

There are Tambol maps available at Suriwong & DK book centers.

There is now a good map that covers everywhere in Chiang Mai province down to the soi level (plus Chiang Rai, Mae Hon Son, Lamphun & Lampang). See this thread: ThinkNet map of Chiang Mai