Hey Bobby,
Welcome to the forum,
as for the model, I think that's a personal choice based on where you feel your talents and skills are. Some people need super detailed plans to feel comfortable, and I have seen others sketch out a basic shape on a restaurant napkin and get to work!

Me? I am somewhere in the middle. I don't think I would do a mock-up, mainly cause I don't want to pay for the extra materials, but who knows; it might save you some heartache. nearly every single build that I have looked at has a few "oh crap" moments where things went wrong.
I am just getting started on my first build and learning tons on the forum. DON'T BE AFRAID TO ASK QUESTIONS, even if you think they are silly. the guys and gals here have probably already made most of the mistakes that you and I will make on our builds. If we ask, we might be able to skip some of them.
One build that I found to be particularly good is Joanne's Desert Dawg, in fact, it was that build that really fanned my interest in Teardrops and led me to joining the forum. She takes lots of pictures and does a good job explaining why she does what. So take a look and maybe it will help you
http://www.asolidfoundation.com/index.shtml <----Joanne's homepage