You are good to go with one exception but the answer to your last question is NO!!! I am assuming that the manual PT, like the automatic, locks the steering wheel when the key is in the off position. You must leave the key in the ignition and turned to the first position to unlock the steering wheel and the steering wheel must be unlocked to avoid damaging your front tires and steering assembly. I have the wagon PT GT and keep the key in the ignition turned to on and lock the doors with the remote control (the interior door lock switch will not work with the key in the ignition). With the convertible, I would get a duplicate key made that isn't programmed. That way, you can unlock the steering wheel but the key will NOT start the car.
Now to the one exception. I would HIGHLY recommend a
Toad-Charge. The brake buddy will run your battery down without it. Obviously, the parking brake should be down before towing also.
I use padlocks in lieu of the pins to attach the towbar to the PT to further reduce the potential for someone to 'remove' the PT. A last minute check should include verifying that the parking brake is off, the steering wheel unlocked and the transmission is in neutral. A good friend blew up the engine on his manual tranny PT by accidentally leaving it in gear.