While I don't know of any personally, I do know Bellingham Wa has a lot of permiculture and natural systems folks. I grew up in B'ham.
B'ham would likely be your main decent US
city to go to. Blaine is just too small and focused on being a boarder town.
Pt Roberts is a tough one though as your stuck not connected to the US. It is easier for you to hang out in Canada than other US cities.
I would however highly suggest going to B'ham and visiting Fairhaven college, where they have some great
permaculture oriented stuff going on. Not sure if it is still going, but there used to be the "Freedom College" basically a low cost no degree education system where you take courses for learning rather than a piece of paper. Many of the courses are the same ones offered at Fairhaven College by the same instructors, but you don't have to pay tuition etc, just a small classroom fee and teacher fee. Lots of good opportunities to connect with like minded folks that way as well was learn stuff.
I would also suggest looking for River Farm events. The River Farm is a great community in Demming WA
http://www.ic.org/directory/river-farm/ they used to hold my favorite festivals not sure if they still do. Rather than a focus on music and vending, they were focused on workshops and education. Really amazing folks out there, and one of the members was the
solar educator at Fairhaven College, as well as for the
Freedom college.
I am sure there is a lot more going on in the B'ham area but it is a long time since I spent any significant time there, and none of my old friends have stayed in touch with me as I traveled around the country being nomadic a lot. For amazing Burritos definitely visit Casa Que Pasa.
As for places to visit on your travels, Missoula MT of course and a visit to
Wheaton Labs. Tonasket WA (the town near my homestead) is a nice little place, not a lot going on there but there are some great restaurants and a few nice shops to stop at while passing through. Ernie and Erica of
rocket mass heater fame live near by there.