Runs in the area: I second the Timpoweap gorge if you want some decent class V, the Park section from the Narrows down to the park entrance is good Class IV with one diversion structure (I'd say just combine this run with your second day coming out of the Narrows). And then there's also Virgin River Gorge outside of St. George. Class III-IV. NOthing too exciting, but some good desert boating.
I grew up in Cedar and paddle Coal Creek a bunch. Not a destination by any means, but some ok micro creeking if you're already in town. Ash Creek I think could be fun, but I've only seen it run 3 times, ever. Beaver creek is cool if it's clean, but nobody cleans it, so think portage fest, especially post beatle kill in the area. Lastly, the Sevier if it's releasing. But it's pretty mellow class III.
Limited options for boating in the area, but if you bring a bike or climbing gear your possibilities are endless. There's also some decent ski mountaineering near Beaver in the Toushars which would be in at that time.