lake creek. yes, you can portage paralyzer. i got out above and portaged that whole gorge. the sneak on the right looked like it would be really reasonable at normal levels. neither of us had done it before, and i think the level was about 675 cfs. pretty stupid high. the water is from a diversion, so it could run for a while. it's been pumping high for over a month now. i think 400 - 450 would be a great level for an eastern kid.
upper south boulder is controlled flow too, and it might be running for a while. it's still pretty high. i did it at 420 or so and it was perfect. lotsa action, comes at you really fast.
other controlled flow creeks are bailey canyon (fun class IV), cheesman gorge (solid V). i've run both of these as late as september.
there will certainly be other options as well....i'm not even local and i can name plenty.
give me a call at work (mon, wed, fri) and i can help you out more with info and contacts. or just find me at the green on tues, thurs, sat, sun.