Is this the first time the water system is being used after winterization? Make sure the valve on the inlet side of the water pump is open. Also, the hose in the service center that is used to draw in anti-freeze needs to be capped or your pump will suck air.
As far as your blue hose goes, it appears as though you have the dreaded case of the drain backs. People have solved this issue in many ways, including a trip back to the dealer in order to have the vent lines rerouted. If this is the case with your coach, it's absolutely amazing to me that RW has yet to resolve this issue.
2012 F350 KR CC DRW w/ some stuff
Cindy and Tom, Toby and Kasey (our Berner and Newfie)
Oh...I forgot the five kids.