Trek 7.3fx vs Cannondale Quick 4

[Owlie]

Welcome to TE!
Giant has the Dash/Rapid series in varying levels of componentry, though I can't remember off the top of my head how much they cost.

In response to your concern about the carbon fork:
It depends--on you and your roads. Different people are differently-susceptible to "road buzz." You won't really know until you ride. It also depends on your road surfaces--if you have chip-sealed roads, a carbon fork is probably a plus!

If you've been researching carbon forks online, keep in mind that no one is going to report instances of their fork not failing! There are lots of carbon forks out there these days. Mine has a carbon fork. DBF's bike has a carbon fork (and is probably...seven or eight years old at this point) and still going strong.

Take them both out for test rides and see what you think. If you want to do a ride of that length, I'd strongly recommend saving for a nicer flat-bar road bike for the future--or buying a bike whose frame would be worth upgrading. Happy bike shopping!