I've done it. Just don't make the mistake of dropping and stepping on the nozzle cuz that will cost you another $40.00.

I do think some of my problems had to do with the regulator. I went through three Camco regulators before I finally discovered the Mr. Heater regulator I got from Tractor Supply seem to be much more reliable.

Unfortunately, the absorption systems do not have a long a service life as they should.  I don't recall exactly what I paid FR for the new fridge, but it wasn't a whole lot more than the parts your tech is suggesting.  You can get plenty of good advice from the board members [and FR] on the installation.

Can you hear it?

If not it needs cleaning somewhere. Sometimes compressed air can clean out the cob webs or whatever else might be blocking the flow. Especially if it has sat for a long time. Sometimes you need to remove the connection @ the solenoid and clean out with alcohol. I carry a syringe just for this. Have had to do it several times probably because of contaminated propane lines. I disconnect, flush with syringe full of alcohol, let it dry, put it back together and check for leaks with soapy water and listen for good flame. Has worked well for me over the last six years.