It's easy to make the current pump run quiet by isolating its vibrations from the rest of the RV. I mounted mine on sections of rubber hose and installed flexible hoses between it and the pex lines, and also added cushioning between the nearest water lines and the walls/floor.
Adding an accumulator (tank) will help with the water hammer, and also allows the pump to run less frequently, which is a boon especially when flushing the toilet in the middle of the night.
The old school pumps use less water than those newer variable speed ones, which could be important if you boondock.