As to where to mount it - it depends on how your plumbing system is arranged. I'm not familiar with your coach but if the existing pump is simply attached to two hose, and you can trace those hoses back down to a location closer to your water tank in the basement, I don't see why not. Actually, having the pump closer to the tank will make it work easier rather than having to lift the water from the tank to the pump.
I have a Shurflo 7.7 Smart Sensor pump. It's quiet and has lots of water capacity - 5.7 GPM. It's a variable flow pump so it doesn't hammer as much as the on-demand pumps which have constant flow and kick on and off to regulate the water output. Because it is so large it soes have a few issues to deal with though. You'll need a high capacity pump strainer to allow enough water to enter the pump to prevent cavitation. It's also recommended to use the flexible hose kit rather than connect it direct to the Pex lines in order to sdampen vibrations from the high water flow. Lastly, you may need a larger water pump relay. The standard 10 amp water pump controllers (relays) may be undersized and starve it for power. Some RVers found this out by burning out pumps so a larger relay and wiring gauge may be needed.
Many are now going with the AquaJet variable flow pump. It's a bit smalller in capacity, 4.5 GPM if I recall correctly, and isn't as picky as the larger ShurFlo.
Mark & Leann Quasius
2016 Cornerstone 45A
2007 Allegro Bus 42QRP (Sold)
2012 Jeep Wrangler Unlimited - Rubicon