teflon tape is bad for any fuel system on any truck with a Oxygen sensor in the exhaust system (the tape part being made of a large % silicone) but your truck does not have an 02 sensor in the exhaust.

I was told that teflon tape is bad to use when dealing with propane, I'm not trying to mess anything up.

thanks for all the help!

You can get a regulator and the filter lock at any place that deals with forklifts, I would think. Should be easy to do (this is your personal forklift, right?). Make sure you use sealer or Teflon tape on the pipe threads of the fittings. No need for sealer on the actual hose connection that has a flair in it. Be careful when you bleed out the LP gas from the hose as you take it apart (tank is shut off but still has gas in the hose). Then take a spray bottle of sudsy soap and make sure you don't have any leaks. Also turn the tank off when not in use.

Is it easy to replace? Haven't seen any videos.

Also where is a good place to get the part? I was told to always replace the filter at the same time.

Sounds correct to me. That's what happens most every time a regulator fails.