I found it by accident, searching for that dang vent solenoid! That hose was literally dangling in my face and I just decided to give it a good hard blow while I was there.
I've confirmed that the vent soleniod SHOULD be mounted right next to the EVAP canister. It would be impossible to miss. The RV manufacturer has clearly done some re-engineering here. There's also no connector on the wire harness, so it's not something that was just ripped out.
I have e-mail pending with the dealer here in town. I'll post more info if they reply.
