[pdxf]

Not sure if this is helpful at all, but the area around Olallie Lake (just north of Mt. Jefferson) has quite a few lakes -- several accessible by road, and others short hikes in (This area is probably 2-3 hours from Portland). There are some pockets of lakes in the Southern Cascades in Washington, some near the Indian Heaven Wilderness and some really nice ones just north of Mt. Adams. There are actually quite a few lakes in the Central Oregon Cascades, but yeah, all of these may be a bit futher than what you're typically wanting to drive.