When it comes to motorizing a bike and being completely new to mechanics, start with what you have. It doesn't matter if the bike is rusted ot beat up. As long as your rims are in good shape and all your cables are in good shape and your brakes work, you can use it, providing the engine will fit in the frame. Pretty much any bike with 26 inch wheels will hold a 2 stroke. As far as hills go, you might have to pedal-assist the engine sometimes, but these engines are made to be pedal assisted. The engine does usually make pedaling a lot easier. If you have a mountain bike, you should be able to make it up even the steepest hills without a ton of pedaling. Being new to mechanics, it would be best to find a buddy that has more experience than you do. A cheap kit is ok to start with, because if you mess something up, its cheap to replace. Don't order from gasbike.net or kingsmotorbike.com. They are the same company, and have a habit of taking people's money and not delivering the product that was ordered.