Thanks for catching that. I don't think the routing in the HB has ever been right; GMSV shows the routing you described in 2008, and on historic aerials back to the 1970s that seems to be the busier roadway. Given that signage is standard throughout Green Camp, I don't consider this to be Updates-worthy, so I'll go ahead and change the routing silently unless there's an objection. No one is using any of the points in question.
As for the northern end, I think we're doing the best we can. ODOT straight line diagrams show it ending at OH 4, which is a one-way pair two blocks apart. The signed route follows the routing shown in the SLD. It may have originally started at Center St if
this 2013 GMSV is to be believed, which would explain why northbound traffic on State St isn't being directed to it. So I don't think we need to change the end points, although I think the point on Prospect is unnecessary and will delete that.