We tow a 2004 Jeep Wrangler TJ series using the Roadmaster All Terrain towbar and XL baseplates. It's a great setup and easy to connect or disconnect even when the Jeep and motorhome are at different heights, or at an angle to one another.
The TJ series (1997 to 2006) and some of the earlier JK series (introduced in 2007) have steering wheel locks. All you have to do to be sure the system is unlocked is to put the key in and turn it forward 1 position. The steering is then unlocked, but the ignition is not on.
A chipped ignition key was an option for the TJ series. If you have the option you need a key with a chip to start the engine. Again if you have that option all you need to do is go to a locksmith (or possibly a hardware store) and have them copy your key onto a non-chipped blank. The key will turn in the ignition, the engine will crank, but it won't start.
If you don't have the chipped key option you can lower the glove compartment and remove the #4 fuse. It's for the ignition system. The engine will crank but not start.
If you have the later version of the JK there is no steering lock, so you can just remove the key.
We use the Roadmaster 9060 towing system. It's a great proportional system, however it takes a fair amount of time and room in the motorhome to install. I like the system, but there are many newer systems on the market that are easier to install an take up less room.