I use the magnetic lights. They work well. For my LJ the common 20' set up is a little short, but should be ok with a TJ.
Don't tie off the steering wheel, the wheel needs to turn and the steering column needs to be unlocked.
My tows have been in the three to five hour range and I just insert the key into the column and turn it to accessories, or what ever the first stop that unlocks the wheel is. No battery issues with the five hour tows.
For longer tows you might want to pull a battery cable.
Also, some guys who have towed TJ/LJ's a lot have a "valet" key made that will unlock the wheel but won't start the Jeep. Otherwise you need to take the key out when you stop to make sure your Jeep is still there after a meal or head break!
Towing the Jeep without the column unlocked is impossible. You will know that for sure after a hundred feet or your first curve.
BTW, my LJ pushes my 2500 Suburban around a bit on highway curves. You need to be thinking ahead and not be going to fast heading into curves.
Edit: Thought it might be a good idea to go through all of the steps to flat towing a TJ/LJ. First you need to have the tow bar connected to the TJ. I have bar brackets bolted through the steel tubing aftermarket bumber, so my bar connect to these. Attach bar when the Jeep ismaybe 6'-8' behind the tow vehicle. I find it easier to drive the Jeep to the ball rather than backing the ball to the tow bar. Twp people make it a breeze, doing it solo might take a few tries. Doing it solo, I use the safety chains to hold the tow bar up to both clear the ball and so I can see the coupler. The chins go aroung a winch/light gaurd bar on my Jeep. Once the couple is over the ball and secured, put the transfer case in Neutral and the transission in Drive or in third gear or higher if manual.
When you arrive at you destination don't forget that the transfer case is in Neutral. I have, and I've managed to uncouple the Jeep and tow vehicle with the transfer case still in Neutral. It makes for an exciting and embarassing sprint to get into the Jeep to stop it from rolling away.
Ussually there will be a load on the ball and decoupling will be diffcult or impossible with the Jeep's transfer case still in neutral. So, if solo, unlock the coupler, start the Jeep and put in 2 high, put in gear and creep a half inch forward to unload the ball. Engage parking brake. Decouple. Solo, it might take a couple of tries to unload the ball without going too far forward and loading it again. With two people its a breeze, just inch forward as the second person pulls the unlocked coupler off the ball.
JPK