Haffner, Grotto, Heart Creek, Junkyards, King Creek and Johnson Canyon are all popular, busy spots with plenty of half-pitch ice and mixed lines so you have good chance of 1) just showing up there and being able to find partners if you are solo, and 2) being able to catch a burn on someone else's already set up TR, and 3) mostly have lines easy enough to solo if there is no one else there when you get there (except Haffner).
If you want something longer than half a pitch but still need to find partners at the crag Evan-Thomas Creek is your best bet. There's usually ppl at the Moonlight-Snowline area (three two pitch WI4s plus a WI2 all within 500m of each other) and there's a new ice and mixed crag called the Rehab Wall another half an hour hike further up the trail (not in guidebook but topo online) with a further 6-8 popular one pitch lines.