I wonder if those who dislike the part close to Bandon are actually talking about 42S, a shortcut at Coquille. That's narrower and curvier as it skirts the south side of the river valley.
Going further north to the actual junction of 101 and 42 might be better for a big RV. I've only done the south alternitive, but that was in a car. It's the kind of local road where you can stop at farm driveways for honorsystem fresh eggs.
My understanding is that 42 is one of easier roads across the costal mountains. You might have to go as far north as US20 to get something lower and straighter.