Since I got Innsmouth I've been playing with it and the Dunwich and Kingsport expansions. I'm curious as to how many others are doing the same and what insights they've gleaned so far.
Obviously the first issue is one of prioritization. With only four Investigators, you're never going to have enough manpower to cover everything you need to. So it's question of what you let go. The Rifts? The gates and monsters in Dunwich? The Deep One Rising track? The Rumor that just came up? Or do you attend to all of these and in so doing neglect gate sealing? I'm still struggling with the best way to keep on top of things, especially since there is often so little time. Last game we had twelve gates open in thirteen turns and there was Shub Niggurath. Ironically, we would have won if stupid Tommy Muldoon had not been delayed and had sealed his gate!
The Personal Stories, aside from being great thematically, are definitely a boon to the Investigators in my opinion. In the game mentioned above, the reason we nearly won is because Silas Marsh (who is an absolutely terrific character!) completed his Personal Story and in so doing sealed the gate at Devil Reef. Then n the first game we played against Cthulhu with Innsmouth Lily's Personal Story gave us a real boost against him. Due to her completion of it and several other factors it seemed we were actually going to defeat the High Priest of Ry'leh in Final Combat for the first time ever. By the time our attack concluded on the fourth round was finished he was down to only four Doom tokens! Of course that was when Cthulhu decided he didn't like the way this fight was shaping up and ate us all his Flabby Maw Sinister Plot. Sigh.
There is definitely a sense of completeness and satisfaction in playing with all the towns at once, at least for me. Despite the great challenge involved, it's hard for me to envision taking any of them out.
Oh, and the Servitor of the Outer Gods has shown up a couple times, interestingly enough in ways that increase his already formidible threat. For example, in our first game against Yibb-Tstill, he was the second monster out! He spent practically the whole game on the board, periodicially swooping down on us and requiring us to get two successes on the Evade check to sneak away from him. Then in the game before this a mutated (an additional -1 to Combat checks) Servitor attacked Sister Mary at Gardener's Place!
The poster who said that Kingsport would see more action with Innsmouth I found right, though only to a small degree. So far we've had two attacks by aquatic monsters on Investigators at the Lighthouse and that's all.