The cabins at Cultus Lake are definitley nothing to get overly excited about. I've thrown a tent down every summer for the past 15 years and stayed in the cabins once. Tent camping is the way to go.
The cabins in Sunriver are really nice but it's not exactly camping/cookout. Sunriver is a destination resort/city. It's about a 25-30 minute drive to the lakes from there. A lot of people may prefer this over camping. There's shopping, pools, tennis and KILLER golfing.
Sunriver Resort:
http://www.sunriver-resort.com/
Crosswater Golf Course:
http://www.crosswater.com/
But like Danbert said it may be easier to find something on the west side of the mountains. I haven't spent much time over there for camping but I'd be down for something new! Anybody got any good places over there?