Doon -
With regard to your question #1:
Yes, that is all it takes to drain the water heater. You don't need to install a bypass, or remove the plug, or anything else.
You can see a diagram of the water system at
http://members.cox.net/wjeffrey/Trai...ingDiagram.gif
It's really quite simple, but this diagram makes it more understandable.
With regard to your question #2:
The manufacturers' web sites are really a good source of information - you should check them. Your answer is in the manufacturer's FAQ, questions 4 and 8, at
http://www.rvcomfort.com/suburban/se..._questions.php.
What it tells you is that some water heaters have a drain plug that is simply a plug. Nothing else. Sounds like you had one of those in your previous RV. By contrast, the Suburban water heater used in the TM combines the anode rod and the drain plug.
It IS a good idea to pull the anode rod occasionally and flush the sediment out of the tank - but this has nothing to do with draining or freezeproofing.
Bill