My guess is that the Trek is too small for you, given you are 6-8. That is closer to the size someone that is 6-2 to 6-4 would buy. Realize there are 2.54 cm to an inch. So one inch addition inseam = 2.5 cm addition standover height.

Head to a good bike shop and have them give you fit advice. You really cannot be sized over the internet, on a forum of any kind.

$475 is a good price, but not for a bike that does not fit.

Based on your description of the type of riding you plan to do, I would recommend one of the better brands of rigid framed mountain bikes (Trek, Specialized, Giant, etc...). They are pretty indestructible, and with the addition of smooth tires, can do well on pavement.