My wife, who normally drives a Honda CR-V, was reluctant to drive a 31-1/2 ft. box. But she started out on the interstates and then moved onto four-lane highways. After a few outings she was okay driving it on two-lane secondary roads in the mountains.
And she really impressed me that time in the Tennessee mountains when we stopped for gas. The station was tight anyway, but after we were committed we saw the fuel truck making a delivery was blocking one entire side. She not only maneuvered it into the pumps, but then backed it out after we gassed up.
After some experience you'll become more comfortable with it. Key points are extra following distance because it's a really heavy vehicle and make wide turns but be cautious of those in tight areas. The long rear overhang makes for a very wide tail swing.
I know. Be wary of getting off the pavement. Ours weighs over seven tons and would bog down quickly if not on a good surface. And watch for overhangs and read those yellow clearance signs. Our height is 11'-6" so I stuck '11-6' on the inside of the windshield on the left side using mailbox numbers. Whoever is driving can easily verify our height with a glance.
Practice may not make you perfect, but it sure makes you better.