From what I've been able to find online, the Park Zone Super Cub uses a 3-channel single stick radio (correct me if I'm wrong). This is different from a full 4-channel setup you'd find on the Nexstar or another trainer. But, if you are using the G3.5 simulator and are able to fly with the full house controller that comes with it (I'm assuming it came with one), then you probably won't have that hard of a time stepping up to a glow trainer. Apart from the actual transmitter differences, you will need to learn to fly with the ailerons. The majority of people are taught to fly using ailerons only, so you may be a step ahead by having used rudder control on your super cub (rudder is useful on sport and scale planes. Trainers can also benefit from its use, but most people don't use it). I think the biggest hurdle when you are learning is the counter-intuitive control reversal when the plane is facing you. As you fly more, it'll become automatic and you won't have to think about your aileron input while heading toward or away from yourself. Also, trimming the plane won't be any different from your super cub. There is just one more thing to trim now (ailerons). Any glow engine you get will require a bit of tuning to get it running correctly. Its not as complex as it sounds and the instruction manual for the engine will cover the basic steps to get the engine running. A "Slow Stick" is an airplane:


I believe its made by e-flite (Horizon Hobby)
It's electric, but has full 4-channel control and as the name implies it flies slooow Plus its simple and will likely be easy to repair if you crash. If you are set on a glow trainer, be sure to take a peek in the Trainer selection thread at the very top of the Beginner's forum. Lots of information and choices explained.

P.S.: I didn't mean to sound terse regarding the caps lock.