From Stephen Preuninger:
Buttahatchee is a very nice class I river, a great class I and II float for rec boats and canoes. There are some good rapids, good fishing and beautiful cliffs. East of Hamilton on 278 there are two bridges that cross the Buttahatchee. The best section (with most rapids) is between these bridges. Its best level is from 500 to about 1500 cfs. A couple of rapids might be pushing class 2 at high water. It has cliffs and a landscape very similar to Bear Creek (West). There are many houses visible from the river. The water quality is better than average here, and the fishing is great. Like most places around here, its better in the winter, and tough to catch at the right level in the summer. It is very rocky and you'll scrape all the way down at low water.
The first bridge outside Hamiltion on 278 is the take out (with posted signs). The next bridge upstream on 278 is a newly built concrete bridge commonly known in the area as "Burnout bridge" or the "new" bridge because a jet fuel tanker truck crashed on the bridge and burnt it up about 12-15 years ago. Between these 2 bridges are the best rapids. I'd guess there are 4 or 5 class I rapids and many good shoals (just a guess, there might be a couple more).
About a year ago, a gate and posted signs were put up at the access point at the bridge closest to Hamilton (take-out). Access is still available at the put-in bridge. I am currently using a nice gentleman's backyard to take-out, so I don't know what to tell you about the take-out. I don't think you'd get shot at the posted bridge but it would be a long carry around the gate.
Going further east there is another bridge on 253 that will take you thru Pierces Mill. There is a old mill dam that you have to portage around. Because of the dam, most of this section is flat water. There are a few small rapids as you approach the 'New' bridge.
I have never paddled upstream of 253 (toward Whitehouse) but I expect its too small except after really big rains.
I know of many older folks that float from Hamilton south to the old 78 or 43 bridge, but the old timers float it and fish it in flat bottom jon boats, so I know that is flat too.
I will go down to 300 cfs. Between 300 and 500 cfs there is much scraping, and you have to pick your lines carefully to avoid the rocks. So I'd say, at 300 your gonna have to get out of the boat a couple of times, and at 500 you won't. The perfect level is 750 to 1000.