LP gauges in RV's are pathetic. Some are just idiot lights and others like on my Winnebago View readout in 1/4 tanks increments, but are not accurate at all. When my gauge reads 1/4 tank, it is actually only half empty. Turns out, most RV propane tanks have a sensor in the tank that you can read directly with an inexpensive car fuel gauge. So I added a $20 gauge and now know exactly what's left in the tank.

Gauge: https://www.amazon.com/gp/product/B00...
DPDT Switch: https://www.amazon.com/gp/product/B07...
Momentary Switch: https://www.amazon.com/gp/product/B07...