There are folks touring the coast on all sorts of bikes , It will be fine, if you can securely mount
the luggage aboard.

I recommend Tubus racks since you asked , And and you have Ortlieb's Dry Panniers.

I cannot help you mount racks from a Keyboard , Bike Shop Mechanics can.
( Nor do I own a Cannondale disc cross bike, But if in front of me Id figure out something)

QR Skewer Mount and seat stay P clips will fit a lot of odd setups.

If the Old 10 speed fits and the low gear goes way down to 1:1 ..
or you aren't tackling the Hills in Donnegal's Mountains ..

though hill walking is always a fine way to see the countryside..