Ken---I am not so sure that Season 6 is the last. There is talk of another; our B and B hostess mentioned that they may be back to film in 2015. And I found this interview with Martin Clunes on the British TV show "This Morning" where he indicates there will be one more season, to get the Doc and Luisa back to "a better place":
http://www.dailymotion.com/video/x1juwb9_martin-clunes-on-this-morning-26314_people
Laurel---we did not see the stickers you mentioned but most of the shops appear to support the show; they sell lots of Doc Martin memorabelia. And the shop that functions as Mrs. Tishell's pharmacy goes all out, with photos and autographs. Out hostess mentioned one business that is sort of anti, namely the pottery at the bottom of the road leading to the Doc's house. She told stories of the potter having to get up from his wheel and clean his clay-covered hands to greet potential customers, only to find they just wanted to know where the Doc's house is. Understandable that he would find that intrusive. Now they have a sign pointing upward, saying that the Doc's house is 3 houses up. And the potter's family has opened a cafe in their building, so they are capitalizing on the increased tourist traffic.
The people who own the house itself have found it necessary to wrap it with a chain barrier and a "Private" sign. Again, very understandable. Apparently people were coming up the steps and peering in the windows! Even though it is only the exterior of the house that is used.
It really is a beautiful place, and I highly recommend the hike on the coastal trail going west to Port Quin, and back across the fields (about 6 miles RT). We actually wanted to hike the section east to Tintagel (10 miles) but that required a bus there so we could walk back, and the bus was not running on Sunday. So instead we did the shorter hike, and then walked over to Port Gaverne so my husband could go for a swim. Yes, it was cold and he didn't stay in long. As we left we saw kids arriving with Boogie boards, but they were wearing wetsuits. In mid-August they run a triathlon that starts with a one-mile swim from Port Gaverne to Port Isaac, then continues with a run on the Coast Path to Port Quin (fairly gnarly with lots of steps), and a 3-mile kayak trip back. The next day they do a Big Swim, 3 miles from Port Quin to Port Isaac. There is lots going on there besides the Doc Martin nostalgia.