The motor should just bolt on nice using a custom front mount(not a big deal you can make one out of a muffler clamp)think the rear wheel has some issues with fitting the rag joint but it can be done,,the gas tank mount needs to be customized a little,,and some are saying the handlebars are too big for the controls(throttle and stuff)other than that you may need to make the hole a little bigger in the sprocket so it fits over the dust cover on the hub and put a little Z-bend in the brake arm/plate,,but heck,,go for it!!
If you want a really easy build do a basic mountain bike(older style)with normal size tubes(v frame)and get the kit with the regular front mount,,not the oversize one.I just did a mongoose alta I picked up on CL and it was very straight forward,,only thing I had to do was bend the muffler pipe,,thats it!
Any questions just ask,,thats why we are here to help you through,,I dont know it all but I know some.
Tom