LP campfire

We have an auxiliary low pressure LP hose on our TT. We also have a "Campfire In A Can". I removed the regulator and installed a male quick connect that would connect directly to the aux hose. Then I installed quick connects on both the input and output sides of the regulator so we could use it with a high pressure tank if we wished. If I remember right, Campfire In A Can actually had the instructions for all this on their web site. Since then I have done the same thing with a Weber Q grill and have a low pressure quick connect Tee that I can put on the aux hose. Then I have a quick connect hose for both the grill and the campfire so I can have both connected and in use at the same time.

I installed a Tee on the high pressure line coming from my underbody propane tank, which I use for my grille and my fire bowl. Works fine.

Coleman makes a "Tree" that hooks to the LP tank and several items can run off the "Tree" I use one for canoe camping, I run my stove and 2 lanterns off it..

You could install a "T" between the propane cylinder and the two stage regulator. Installing a valve and a cap or plug onto the "T" will make everything fairly safe.

Presumably you could bypass the regulator on the campfire unit assuming it's not regulating to a vastly different pressure. Depending on how it's constructed, that may be simple or rather complicated and impractical.

It is certainly possible to install a high pressure fitting of some sort for this (or other high pressure appliances), and people have done it for various purposes. Properly done, I don't see where it would be any more dangerous than toting around a 20 pound tank with its high pressure fitting, and probably safer overall. Improperly done, I wouldn't want to be nearby if at all possible.