New to MOC

[DiamondLakeDuo]

Good morning!
My wife and I are new Montana 5th wheel owners and are excited to have found this club of fellow Montana owners. We upgraded from our Keystone travel trailer of 8 years to a Montana High Country 330RL this fall and are most anxious to try it out this winter when we leave the snow behind in Washington State and head to Arizona. Just curious, is there a group of 330 owners within the club?
Other questions regarding the hot water heater: our old travel trailer had an on/off switch behind the outside heater cover. We always turned this off when we disconnected the water hose. Then when we hooked the water back up we would check the pressure relief valve to see that water was in the heater before turning the switch back on. Since the 5th wheel has the heater switches inside the trailer control panel, is this where I turn off the heater for traveling? I see there is still a switch at the outside cover. Does this stay on or should I turn this off also? Do I check for water in the tank with the pressure relief valve? How do I heat the water when using water in the holding tank? Just a little nervous with these unfamiliar controls. Would appreciate any assistance. Thanks in advance. Looking forward to learning more about the world of Montana 5th wheels thru this club.
Safe travels everyone!
Steve and Jan
DiamondLakeDuo
MH 330RL, F-350 Super Duty diesel