Gasbike.net and Kings are the web sites for Nationwide Access since ~2010, they are the official importers of motorized bicycle parts from China Gas, which represents the Yaun Dong engine factory.
In short Nationwide is just box shippers for China MB volume cargo around the US for customers.
For the most part people at Nationwide are just your typical Wallmart checkout person so don't expect detailed information about how to do something with your purchase these days, but if you watch you can some really good deals on quality.
The thing is, with all of the web site install help and guys like me that don't need any help, I find the GT5 66cc engines kits to be top notch after 70+ builds with them and only 2 catastrophic failures since 2009 and both attributed to no oil in the gas.
gasbike sells the 'box of parts' delivered for $175, just ordered a couple more yesterday, what I like is you order it as individual parts with 55% off every part.
The cylinder, piston and head are separate as is the magneto so just a 'box of parts'.
With it already apart you can see the quality of the parts, in other words I don't have to break out a Dremmel, it's ready to go and 99% start up first try.