gasoline RV generator vs propane

Having two 30 lb bottles in our TC makes generator use easy without worry of running out. If we plan on being out longer, we usually have our trailer with us which carries an additional 100 lbs of LPG.

joel...you might want to tell us why you need the genny.

For us, we need a genny only when we need heat...which is also when we need the most propane!
So running our H2K on gas makes the most sense for us.
Running heat and a genny off propane...you can eat up 2 on board tanks pretty quickly.

If you only need the genny for "convenience" (micro/espresso machine/ surround sound TV) then propane is certainly convenient.

I much prefer my onboard propane Gen set to a gas set up. My TC has 2 7 gallon tanks. I have never run out of propane while running Genset to power AC and Fridge and stove. To qualify that statement I seldom if ever am gone for more than a week.
As to which is more efficient gas or Propane. Well Propane costs me $2.25 per gallon and gas is $3.39. Propane runs much cleaner. My onan does not even have an oil filter. Oil change every 100 hours. Holds 1 quart of 10W40.
Carbon monoxide is 20 to 40% lower for propane than gas.
My choice
Propane

If you have a large built in propane tank, it's a decent option but on a truck camper, you likely have 1 or 2 BBQ tanks and you can burn thru those very quickly. Then your fridge and stove are out of commission.

Otherwise, the hassle of getting propane tanks filled makes gas a more appealing option.

Assuming you take care of it and use it with some regularity, both will hold up just fine.

If your proposed gas generator has a fuel pump then using an external marine gas tank with appropriate connections should work just fine. If no fuel pump on generator to draw fuel it's not going to work unless maybe you can position the tank above the generator.

I have had both gas and LP generators in my motorhomes. I prefer gas because you only have ONE fuel to worry about.

In my experiences, propane is much quieter.
And you don't have to handle, or store gasoline.

A gasoline powered generator will have more power or be more efficient than its LPG counterpart but will burn dirtier and will be less tolerant of old fuel sitting inside.

I used to have a 5500w generator in my toy hauler and never had gasoline fuel problems, but it was run twice a month.

The Onans are louder than a Honda or Yamaha but about he same as a Champion.

Most good (Honda Yamaha) gas generators can be converted to propane

No have not, but have recently been looking at fifth wheels with gas generators.

The Jayco Pinnacle has a built in gas tank in front of their generator prepped units to supply fuel for the generator.

Now, all this long winded explanation just to say that I have been told that a gas generator will, for the most part, be more fuel efficient when compared to that same generator on propane. FWIW, and it was a salesman who told me, so buyer beware.