I've done little floating of the Wilson, and that's pretty much been in inflatables (bank fished it literally hundreds of times), but seems like even 4.0 is for the brave.
At its current level (which spiked from a steady 3.4 to a whopping 3.5), a you'd spend more time getting a DB through stuff than you would fishing, and you could probably wade/hike it faster than you could drift it). Once the rains come this fall, then game on.
If a person was really bound and determined, you could probably do below Mills. Less boulder fields, and dragging it would be pretty easy... and you will be dragging it.
Tough time of year to use a driftboat for its primary purpose. A little motor sure makes it a nice tidewater boat, though. And electric motors can be used upstream on many coastal streams, where gas is prohibited.