I have a different model RV than you (334QS) but expect you have the ability to visually watch the water fill the fresh water holding tank. You should consider filling the tank to a level less than completely full. The way FR installs the overflow tubing the tanks have a proclivity to drain fresh water out the overflow tube while you are driving the MH, especially when going up grades and making sharp turns.
Some people have reported loosing almost a /2 tank of fresh water. You might want to search this forum for "fresh water", "water tank overflow", etc.
John & Gloria Hunsaker FROG Member CA-0030-988
2014 Georgetown XL 334QS (class A with 4 slides)
2013 Smart Car TOAD
Blue Ox Aventa LX tow bar, base plates, diode kit
SMI Stay-IN-Play Duo auxiliary braking system
25' Off shore blue water fishing boat