I guess the bigger question is which rig? Also, if you are truely looking at an overlanding adventure, say to the tip of South America, then I this is the recipe I would follow:
Lift: OME 2.5 lift with heavy rears, add a set of air bags ($80) from Summit. Keep it as low as you can, trust me it is cheaper and way less headache.
Tires: Toyo M55's in a 255/85r16 or 285/75r16 (the miners and ranchers swear by them) they are extremely tough tires that are a good mix between an A/T and M/T.
Gears: 1FZE=4.88's /3FE=5.29's, that should help with the extreme elevations in SA, plus pulling the trailer, you would probably get better mileage than with the stock gears with 33's
Comfort: Definitely a real refrigerator, they make you question how you got by without them once you use them.
Winch: Sure.
Lockers: Not so necessary, you can drive a car to the tip of South America, people do it all the time. I'm not saying you can't have fun along the way, but remember your rig is your lifeline and breaking REALLLLLLY sucks far from home.
Dual batteries: yes, mainly for being able to jump start yourself and something along the lines of a Ready Welder. Things will fatigue and you will be able to fix it yourself.
Some kind of air source: Either York, Sanden or even one of Warn's winch/Air compressor combos.
Some way to carry extra fuel, that will be a huge peace of mind in those out of the way places when fuel may be a week or two out from being delivered. I would also carry an extra fuel filter or two. Also basic tune up items.
Biggest thing is to ensure the rig is in as good of shape mechanically as you can make it. Even if you think its ready, double check it and replace anything suspect before you leave. Much easier here than trying to find it on the road.
Plus keep it looking as stock as possible and maybe even as unattractive as possible, I wouldn't add a snorkel or anything to "bling" it up.
That would be the basics.
Now having said that, everyone says to not overstress the vehicle, just go.
Jack