ikold,
You may want to prepare your signature (the vitals for your truck that appear at the bottom of your posts) so folks can better answer questions. I think you go to 'User Control Panel' to do that.
I definitely agree you'll get a variety of responses. IMO, preventative maintenance depends alot on how you use your rig and power mods you've made. Our trucks are making similar power, but you use yours harder, so it's tough for me to prescribe a schedule for you. With that said, I'm changing ATF and transfer case around 30k, diff fluid (both) around 50k, and crank lube at 5k. Brake fluid and coolant every 2 years (will be adding power steering fluid to this schedule next time). Grease steering linkage every other oil change. Valve adjustments per owner's manual. Check brake pads every tire rotation (approx 6 to 8k). A/T band adjustment every other ATF change (60k). I follow all this unless I've got a big trip planned, then all bets are off and I go on a maintenance furry and restart all my schedules.
Now, as far as tip-top shape, and I don't mean to offend anyone, I would recommend researching your local area and finding a couple of reputable shops that can do the things you can't. That is, shops other than dealers. I'm lucky to have a top-notch alignment shop, diesel mechanic, Cummins shop, and A/T shop close by. So far, I've only gone to the alignment shop, but I know where the others are if I need 'em. You may have a great dealer, that's good you'll need one of those too, but for technical work I choose to place my trust (and coin) elsewhere. The good news is that as long as you have a watchful eye these trucks are durable and rather hard to hurt. Good luck.