Kudos to you for your passion for RPM.... yea, it's that good. 
Keep in mind however that riding on your own will never be RPM without a trained instructor to guide you through the changes in cadence and effort. Even when I ride on my own as an instructor, practicing a new release, the essence of the program is just not there. Also any songs you download will likely not be the same "mix" as RPM. The crew in New Zealand tweak them a bit
Keep the passion, demand more classes
“A lot of people have gone further than they thought they could because someone. else thought they could.”
-Zig
Teaching RPM™ and BODYPUMP™ in Bowie Maryland!!