I think the above suggestions are pretty spot on. If you can afford the 450, I think you would be very happy with that. From what you say about your plans, that would be the better route to go. With the added stability of the dually, and the power of the new 6.7L and 6spd Torqeshift tranny, you should be set for just about anything.
Ed and Sharon
2010 Wildcat 28RKBS
2011 Ford F-250 XLT, 6.7L PSD
Ride-Rite Airbags and Airlift wireless remote compressor...nice!
I thought I was wrong once, but I was wrong!