I've been running my pickups on propane for close to 15 years and nearing 200K miles combined on DIY conversions including my 99 Ford F250 with the EFI V10 that near 100K miles on propane itself now.Natural gas is used where it is plentiful. My old mechanic, use to modify cars and other engines for propane. Problem is the distribution is limited.
On edit....it was 20 cents cheaper.
You can get your mechanic to modify your vehicle. You can always get 20 lbs just about anywhere.
My last fill was 82 cents a gallon Vs $2.34 for gasoline so it pretty hard to argue against the conversion around here given that fuel price difference.