My Newmar is the same, no gravity fill ; BUT ; it also has a valve and a pick up tube for RV anti-freeze that hooks to the 12 volt pump .
If I place the tube in a 5 gal. jug and turn the valves the 12 volt pump will draw the water and turning the tank fill valve, runs the water into the fresh tank in 2 minutes .
Have a look to see if your new coach has anything similar .
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.