This is the link to the one in the photo:
https://www.amazon.com/dp/B07ZCJZC3H...lig_dp_it&th=1
If your RV has a twist-lock connector already, make sure you use the same one for the front connector, so it is compatible with the OEM cord you have. Run 10/2 with ground Romex cable (or larger gauge) from the breaker box to a junction box on the front of the RV.
Option 1. You can use your OEM power cord up front to connect to the generator and/or the shore power or, make a short cable with the plug for the generator on one end and the twist-lock on the other end.
Option 2. You can come out of the junction box with a 10/2 w ground, black rubber cable, with the generator plug (this allows you to leave the generator connected, ready to go).
With either option, you will need to add a transfer switch between the input twist-locks and main breaker. *The transfer switch needs to be installed to keep the twist-lock plug not being used from being hot and back feeding the generator when plugged into shore power*.
You can find the plugs and receptacles on Amazon, Ebay and sometimes at Lowes or Home Depot. The twist-lock connectors should have a NEMA number on them. The NEMA number will help you match up the plugs and receptacles.
I was using a 3500 Predator Generator. It had a twist-lock 30-amp receptacle on it. When I upgraded my RV from the "stuff-it-in cord to the twist-lock plug, I made sure to use the same NEMA connector on the RV. That allowed me to make a 6' cord to plug the generator to the camper and also use it as an extension cord with the original cord when at the RV park.