Floated the first 5-6 miles 5/18/14. That stretch was swift Class II with no portaging necessary. My estimate-comparison is that at low-medium levels Gravel Creek is comparable in difficulty to Glacier Creek in Gwood at 26.5’ level. Gravels seems to pick up in difficulty slowly and steadily as elevation increases. I look forward to going to back to the glacier and floating the entire thing.
Hiking is good on a literal “logging highway” - rough and obvious doubletrack that can get wet and muddy but isn’t nearly as bad as the ATV trails across the Mat in the Talkeetnas. The doubletrack trail seems to cross the creek a couple times. With low brush levels at this time of year, it was easy to avoid one ford and follow a game trail back to the doubletrack to avoid one of (what seems to be) two fords. In hindsight, paddling revealed that the creek is consistently shallow - but it’s dirtiness (similar to, but not as bad as, the Mat) and swiftness made the fords seem more intimidating than they probably really are.
Due to the transitions (from paddling to hiking) necessary, long hike, and continuously swift Class II-III water I think this trip would best be done as a more casual overnighter to get the full length of it.