my experience with Internationals was complicated. All the newer 4700s were built strong, tight, and very quiet (in the cab). On the other hand I drove spring and air ride 4700s and neither one rode acceptably. The air ride really surprised me. My friend test drove it with me and he told me,"Take this thing back, it's knocking my teeth lose". The air seat made it tolerable, but the passenger seat was not air.
I ended up with a freightliner for that reason more than any other.
I don't know how much power you need, but I used to own an Isuzu that handled great, and didn't ride that bad. It's main problem was the cabover design made it slow in the highway. Imagine driving a truck with a garage door on the grill.
This may be a stupid question, but does anyone see anything wrong with bigger Ford?
Doc Weaver '98 Freightliner FL60 pseudo toy hauler