I remember when natural gas came to town. We were installing a new furnace anyway so that was no problem. I don't think that it took half an hour to change the jets on the water heater and the kitchen stove, truly trivial operations.

You should be able to find several places in any large city that do petrol to LPG conversions. A diesel to LPG conversion requires that you still burn some diesel just to get ignition so the amount of diesel fuel actually used will be much lower.