I drove from Houston to Smithdale, MS (6 hours, I-10) and the next day from there to Mobile, AL (4 hours). The car will do fine. You'll do fine... may need to get out and stretch a couple of times but that trip was by far the most comfortable 6 hour drive I've ever taken. Heated leather seats were great, and I never got a leg cramp like I have in other cars. Without cruise, you'll get tired of holding the pedal but it's only a few hours, you'll be ok.
Just watch for crosswinds - if you expect them, slow to 60 and let people pass you. Two hands on the wheel and you'll be pretty darn safe.
Grab some poutine on the way, it'll cheer you up.