Ed,
I think that G2 is a great training aid for getting used to controlling the airplane in unusual attitudes. My advice would be to practice some of the more traditional maneuvers like knife edge(both sides) and then work into the harder 3D stuff.

Unfortunately G2 has some limitations with some of the more extreme maneuvers like blenders. That being the case it won't give you everything you need to become an accomplished 3D pilot but it will get you started.

I started out by working on knife edge, you can use the small CAP 232 that comes with the sim for familarity with the maneuver. The small cap requires some speed to maintain altitude while in knife edge flight. Once you have the feel of knife edge move into slow rolls, these combine knife edge stick inputs during the roll and to do them well require a LOT of practice and coordination. Start out with the little cpa and the move up to the CAP 232 2X available from the Realflight downloads page. The larger cap will fly much slower but getting the rolls and knife edge down with the smaller one will help to "round" out your technique. Knife edge at slower speeds requires a lot of throttle management. Just remember, you are going to crash A LOT, don't give up, just keep at it till it "clicks" and it will.

After getting this far you can move to hovering to get some practice with orientation of the airplane in a fully stalled condition. The big CAP actually hovers pretty easily but also loves to torque roll so I don't consider it the best first plane to hover in the sim. There is a large Ultimate that is available for dowload that is not very realistic in level flight but is a great hover trainer. Just remember when the plane is in a hover and turns it's belly towards you, you will have to push the rudder stick towards the low wing to shove the fuselage back into the vertical.

I can't stress this enough, practice hovering DOWN LOW and right in front of you. Attempting to practice hovering up high actually makes the task more difficult. Yes you are going to crash a lot but like I said above just keep at it, this is where you are really going to appreciate having G2.

Once you start getting it down on the PC, if your like many of us, you'll think your ready to try it with the real thing. Just keep in mind that while G2 is great for getting you mind and thumbs working in the right directions, real airplanes will still throw curves at you. I felt like I was starting a whole new learning experience but had a LOT more confidence after getting used to flying on G2.

Patience
Practice
Persistence