Common people – answear!
I think your best bet for meeting outdoors people in Snæfellsnes are the rescue teams, see if you can hang out with some of those guys.
Then I think there are some people in Borgarnes and the surrounding area (not THAT far) and at the schools at Hvanneyri and Bifrost that are venturing into the hills.
Lastly, you should consider driving to the Isalp events. Often they take place in your direction so it’s not that far.
You can find the event calender here (in Icelandic though) http://isalp.is/program.php
FEBRUARY
17/18: Course in winter mountaineering
23-25: Iceclimbing festival
MARCH
10: Skessuhorn, a beautiful mountain near Borgarnes (maybe hours drive from you) via a excellent classical and not that technical scramble ridge.
16-18: Telemark festival in the north
18: Miðsúla – another great mountain
APRIL
21/22: Tindfjoll – an overnight trip, climbing some peaks in the cradle of Icelandic alpinism.
If you show up at some of these you will meet like minded people.
Then you have the glacier, lots of iceclimbing, trad climbing at Gerduberg, some nice peaks like Kirkjufell and lots of stuff to do near you.
Regards,
Sissi