my name is Daniel I live in a rural community in tennessee, I am a golf course mechanic, with over 20 years experience in small engines, recently due to the price of gas I have been thinking about getting or making a motorized bike, I travel 40 miles a day 20 each way to and from work, I have several questions such as what is the average speed of a gas powered bike?, and how are they when it comes to hills, any thoughts and suggestions would be appreciated.

Welcome to the forum..
You can ride one of these bikes 20 miles each way to work, but I'd wait until you get some break in miles first.

Hills? How big?

The speed on the frame mount is around 25-35 mph, one built with a weed eater engine or chainsaw engine will still do about 30, but take longer to get there.