I tend to do a lot of low angle stuff. Here are the three places I go most often that I would call backcountry:
Kendall -- There is a long approach, but the drive is easy and you can definitely get into some nice backcountry skiing. Even if you just poke around the lake area it is fun, easy and wild. But the road is not totally safe -- there are spots that have avalanche danger (as do other areas of course).
Artist Point -- This is one of the easiest and nicest backcountry places out there in my opinion. There is a groomed section (that is shared by the ski resort) but it is fairly short. The tour itself is fairly short, but extremely pretty and wild on a nice day. I'm not sure if dogs are allowed.
Paradise Area -- There is a lot of low angle terrain around Paradise. No dogs allowed, though.
Park Butte -- There is plenty of low angle terrain here. This is the only place on this list that has a lot of snowmobiles, which I find irritating.
I believe all these areas are mentioned in the books (backcountry skiing or the cross country ski tours books). I would buy those books. They go into a lot of detail and tell you (roughly) what the avalanche danger is and what to avoid. You shouldn't rely solely on that information (of course) but it reduces the chance that you will only go a little ways and then turn around (you wouldn't want to pick a ski tour with a moderate or higher avalanche danger this last week). It also reduces the chance that you will simply follow an old track and trigger a slide, when there is a much safer way to go (e. g. the route to Artist Point).
