I currently own a Trek Fitness 7.4 (fully capable of being a road bike according to Trek) and was wondering how far I could reasonable expect to ride the bike. I know I this rig won't be the fastest bike on the road (not riding in any group rides) but, I was expecting to be able to ride 30 - 50 miles on weekends and maybe even 100 miles. Am I living in a dream world? How far do you ride your hybrid bikes?

30 to 40 miles every day, occasionally 50 to 60.

No reason it wouldn't be fine for 100 plus. The ones who say you can't ride long distance are all wet. Many people tour on them.

As long as it's setup properly, I don't see why you can't ride as much as you want. As Wanderer has pointed out, people do tour on them.

IMO the only thing limiting you is your fitness level. I used to ride 30 to 40 miles on my '97 Bianchi Advantage hybrid (and your Trek is probably several lbs lighter and perhaps a grade or two higher components as well). Today, my 11 year old son rode my old Bianchi 25 miles. So, get out and ride, you might surprise yourself.

As said above, if fit is OK, you can ride your hybrid as far as any other bike. I've ridden 100km on paved/dirt roads, no problem

I just commute to work on mine, about 4 miles each way ... A fitness hybrid...( no suss. Fork ) aka : flat bar road bike, With the right tires AND bar ends (so there's more than one hand position) they should be able to go as far as a road bike ( being pedaled by the same person or someone the same fitness level as the guy on the fitness bike )...

A colleague of mine toured from San Francisco to New York on a steel framed Trek hybrids with bar ends.

You can ride as far as you want to ride on it.

My longest rides have been on my hybrid (Trek DS 8.4). (Over 100 miles)
Second longest rides have all been on my mountain bike (Specialized Hardrock Sport FS). (Over 100 miles)
My shortest rides are on a road bike... I'd rather look around and see stuff when I ride. (Way under 100 miles)

Concur. I toured Europe on a cruiser (bike got stolen in France, and only option I could afford where I could get a new one was a cruiser) that was 25 kg. Wasn't the best idea, really, but you can keep going in pretty much anything if you want to (and one of my mates did it on a fixie for a while)

Usually 150-240 miles a week, depending where i want to go.