Need help with a few questions, re: buying first diesel

I am a 4WD fan for towing, you don't need it often but when you do you will really miss it. Wet grass, big muddy puddles, grades all found in CG can call for 4WD. It also expands your touring range greatly out west. I assume it is an advantage in snow but have minimal experience consisting of pulling a fellow out of a snow bank in the WY mountains. I think you need 4 sets of chains tho.

4WD is heavier and will supposedly reduce mpg by 0.5 to 1 mpg. It also makes your truck higher by a few inches.