I got mine back from the dealer and she's all good now. On the 350 access is quite tight but after the spray foam around the area and around the hose to the anti siphon valve was removed, it made it much easier. Also, the water heater was attached to the flip up panel which required removal of the water heater flashing and some disconnection to gain access. All in all it was 5 hours of labor for a $10 part!
I'll post some pictures once I get them from the dealer. On that note, anyone in the Quinte area of South Eastern Ontario needing a great Forest River dealer contact Carl Cox RVs, 613-966-9200. Glen Cox is the service manager.
2013 Georgetown 350 XL
2009 Pontiac Vibe toad