There are ways to modify the stove to use the low pressure fitting in most cases (not all) epically if the regulator is removable. HOWEVER I can not tell you how to do it (Model specific)
The only model I know well enough to advise. I would NOT suggest you buy (I have one you see).
Also the fitting may be hard to find (Coupler)
Better to go with the current equivalent of the "Extend-a-flow" This was one of two adapters for the HIGH PRESSURE side of the propane system that I used to use when I had a trailer.. The other one (Extend-a-stay, now called Stay-a-while as I recall) I now use with my Class A Both work well and use the Grill's bulit in regulator. Marshall Brass made the "Extend-a- models" but they stopped making them near as I can tell.. Still in business, just not those adapters.
Mr. Heater I think is the "Stay-a-while" But if you go to a RV store and ask an employee over 30 for the "Extend-a-flow" he will likely know.. I may have to add a decade though.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times