We have a 2013 Redwood 36FB, we opted for the Fors F-350 Diesel Dually and have no regrets.
These coaches are heavy and you need a truck capable of not only handling the weight but even more importantly...able to stop. A 350/3500 is minimum, you might even may want to consider a 450! Do your homework, do the math and ultimately I think you'll agree.
Good luck...you'll love your FB...we do, the big shower is wonderful, so is the washer/dryer!!!