at this link.
The first page is a list of studios, with addresses and phone numbers (in case you need directions!) The second is a map with markers for each of the 35 studios. The tour is laid out as a loop, starting in Kennebunk and through the studios in the Lakes Region, then turning back through the Portland area, up through Bowdoinham into Central Maine, then down the coast from Warren to Arrowsic.
But hey - start wherever you like! There's a lot to see.