I purchased a 1998 Ford F250 that runs on CNG. The CNG is not redily available in our area and I would like to change this over to propane or gas. Has anyone had any experience with changing this type over?

 

You should have investigated the fuel availability first.
Both systems are very complicated let alone a conversion.
A conversion not only involves the hardware but the computer software calibration as well.
I would put the truck up for sale where out of area interest may be found.
I have seen posts here from people in other countries that got one or have issues.
There is no one to service them in many cases.
I hope I did not insult you but to bring the practcal part of ownership to light.
Good luck.

 

You are already halfway to saving a lot of money on fuel. Have you thought about putting a VRA (Vehicle Refuelling Appliance)? You might even be able to rent one from your utility.

BRC Fuel Maker - FMQ

 

A factory Ford CNG is bi-fuel, which means you can already run it on gas. Shame on you buying a CNG vehicle in an area where CNG is not freely available. Sell the truck to someone who actually needs it and buy a regular gas truck.