I'd avoid Sonora at all costs when towing especially East to West. You're up at several thou feet already with low power, and there is one hill where you make a sharp right turn and can't get the rev's up. You'll be crawling in low gear-we did it a long time ago in a car and tent trailer and I could have walked up faster than we drove, floored in low gear. Did it again in the MH a few years ago and it was the same slow crawl, flat out in low. Tioga is a breeze plus really a beautiful ride but you have to pay for park access.