If you put in a few hours of sim time, there is a good chance you can solo within 3-5 flights with an instructor. Without the sim, it will take you quite a bit longer. The hardest part of flying RC planes is learning the control perspective, or how to control it when it's flying towards you, away from you, above you, inverted, etc. This is something that is best learned with lots of practice. The sim allows you to put in several hours of practice at home on your own, and figure that out. Then at the field, the instructor can give you tips on you flying style, take-offs & landings, etc.

I'll put in another vote for the Avistar for your first trainer. It has less dihedral than most trainers, and a semi-symetrical wing airfoil, making it much more aerobatic than the typical trainer. This means it will be more fun than the typical trainer after you've soloed.