If it takes two hands and any significant effort to control the wheel when trucks pass or on windy days something is wrong. With the proper alignment, tire pressure and loading there should be very little shove from a passing truck. Sadly not all C's are created equal when it comes to ride and handling. A thorough test drive before you buy to include some interstate time where you can experience the effects of passing trucks will eliminate surprises down the road.
Get the rig weighed and check your tire pressures based upon the tire manufacturers inflation guide for the actual weight they are carrying. Get the tires right and then look at your alignment. You should be able to let go of the steering wheel {yes, keep your hands hovering close by...}, and have your coach track straight down the lane without drifting. Also look at the tires for any signs of uneven wear indicating alignment issues.
:C