Adding a port to your Motorhome propane system is easy and works well and is safe. I do recommend that if you are not qualified to add parts to the LP system that you hire a qualified person for this 15 minute job.
The part you need is: Marshall Excelsior G-415 Extend-A-Flow Tee ME415P
Here is a link to it:
https://www.rvsupplyparts.com/catalog/extend-a-stay-propane-adapter/marshall-excelsior-g-415-extend-a-flow-tee-me415p-9906.html
It installs between your shut off valve and regulator. Marshall sells the correct hose in a twelve foot length to then attach a BBQ, portable campfire, gas lights etc. The hose is approved for use as well. The hose is sized to fit the small regulator on most portable BBQs etc. It is the same sized thread as the top of the small 1 - lb disposable LP tanks.
We have a Road Trip and installed the Extend-A Flow. We never buy small canisters anymore. We have a "Little Red Campfire" as well and connect it to the RV gas for use.
It is safe, approved for use along with the accessories and saves you money.