As an alternative - add an 'extend-a-stay' tee to your rv propane...
https://www.amazon.com/Marshall-Gas-.../dp/B002UC4T6C
Goes between the tank and regulator - and allows two things:
- Run RV from a portable tank to extend your stay (where the name comes from)
- Run a gas appliance from your RV propane (appliance needs its own regulator - which they would have if running off 20lb bottle already..) - just need an adapter to go from 'disposable bottle' fitting to your appliance hose.
You already carry plenty of propane - just carry some hose instead of another tank.
I've only carried an additional empty tank - for a 6 month stay where I thought I might need to supplement the RV supply - easy to fill where we were staying - and much easier than moving the RV to refill.
I regularly run my propane grill off the RV tank when camping... and recently at home when I discovered an empty portable tank when it was time to cook dinner...
If you are transporting a separate full propane tank - insure it stays upright and is ventilated...