Faroe78, Hi and welcome. Sorry that I have not responded earlier. This is a great site for advice and support.

The bikes you have been looking at are exactly what I would suggest. Hybrids are great for new cyclists and they can be used both on the road, and on gentle off-road options. I went straight for a racer when I started cycling. I do love the speeds I can get up to on it, but it is not as comfortable as a hybrid on poor roads. I can never take it onto a gravel trail which does limit my options, and if you aren't used to drop handlebars, or haven't used them for a while, they can be very uncomfortable. A mountain bike would also be less practical if you want to cycle on the roads, as the wide, knobbly tires and suspension mean you put in more effort to go the same distance.

I've just been looking up your Trek Navigator and found this review:

"Pros
Versatile, inexpensive, fun, comfortable. Good frame

Cons
not for serious cycling, weak components

The Bottom Line
This should be available used for a song, and will be a great second bike or starter bike

I bought this bike to induce myself to get out and exercise, 3 years ago. It now has almost 4,000 Spring through Fall miles on it. Great frame, long like a tourer, it smooths out bumps. the factory tires are still good. The chain wore out at 3,100 miles, and the bottom bracket too. Replaced both with better quality units. Great bike as is from the factory for rail trail rides and smooth pavement as well as rough, and light off road trails. The upright position is tough in headwinds, but great for sore backs. I added triathalon style aero bars for head wind use. I also switched to 1.5 in 100 psi slicks for a recent MS150 ride. the shifters are not well suited to heavy use on tough hill climbs. This bike is good for rides in the neighborhood and local tours of up to 20 miles at about 12 - 15 mph average speed. Longer rides like the MS150 are better with spd pedals and a narrower saddle (I put welgo spd/street dual use pedals on and a Brooks Conquest saddle)"

Don't know if this is any help. I also found reviews for the Trek 7200 on the following website, you will have to copy and paste the information into the address space on the computer (I don't know how to insert a hyperlink I'm afraid)

http://www.epinions.com/content_131788672644

And they also do reviews of K2s, but I don't know which type you were looking at.

http://www.epinions.com/bike-Bicycles-All-K2_Bike

I hope you find this helpful,

Good luck with your cycling!