I purchased a Ford F-450 dump truck about 8 months ago. It's a 2000 year model, with the 7.3 liter diesel, auto transmission, dual rear wheels, and 4x4. The diesel has started for me without a problem, even up here in North Dakota. I do have a block heater. I wouldn't attempt to start the truck without first warming it up a bit. I like to use the Knipco kerosene heater in addition to the block heater, as that thing will warm up the transmission, rear end, differentials, wheel bearings, etc.
As far as 4x4 goes, I don't think it would be of much use to you. I'm not all that impressed with it. The dual rears make traveling through the snow all but impossible. I think you'd be better off with a set of chains for the rear wheels.......though they aren't very convenient to install and remove. I haven't tried the 4x4 in the mud yet, but I have a feeling that it wouldn't be much different than in the snow.
My used truck once had a snow plow mounted out front. I can see that the plow was very hard on the front end parts. The steering linkages and tie rod ends are all but gone. This is a common problem on any vehicle with a snow plow mounted to it......it's not just a Ford thing.
You'll love the heavy frame that Ford puts in their heavy trucks. There is nothing out there than can compare to the Ford truck frame. It's HEAVY DUTY. The differentials and axles are also very beefy. I'm impressed with every part of the drive train. Every component is large, heavy, and built for hard work. The body is great. Doors and windows are tight. More importantly, to me, is the ride. WOW. That heavy dump truck rides like a Cadillac. I'm very impressed with the comfortable ride and the amazing amount of cabin heat.
Hope this helps. Good luck with your new Ford truck.
Joel