Lloyd,
Here is a brief and general run down on your questions.
Software? Adobe photoshop or Jasc paintshop pro would be best to start with. A lot of people will work their profiles or line art in Illustrator, which is a good choice, but the learning curve may be discouraging for a newbie.
You can never have enough textures. Is it something you need to collect? I guess its a matter of how much time you want to spend on the art. You can find lots of pre-made textures on the net and what not. I generally make mine or use my digital camera to get what I am looking for.
I would suggest the Windsock Datafile special for the DR1. Its a good general source of visual info on the Dr1. Also as you have on your site lots of photos to look at and study.
One thing you will quickly find is that all the cool schemes have already been done by somebody else. Dont let if bother you too much. If your work is original in execution then it is unique. There is always a new and fresh way to represent what has come before.
I have some old tutorials on my site. They are geared towards "skin" creation for flight sims but I think they are general enough to pershaps be of some help to you.
tutorials
hth