I would start with the normal suspension lift, 50mm aftermarket springs in rear and then wound the bars in the front to match. Shockies will make the ride better but not something I would spend on first, especially if the truck has low K's.
Bigger tyres would be next, the 3.5 will easily handle 33", everyone has a preference for a tyre A/T or M/T, but it comes down to what and where you are going to do/go in the truck. A set of Cooper STT's would be a good choice for an all around tyre, not to chunky (enough to get you through that bog though) but last a while.
Good money would be spending on a locker in the front then some frontal and side armour next.
And the list then goes on............................................$$$$$$$$$
Dollar wise:
Springs = $250-300 (NZ Dollars)
Torsion Crank = Your time
Tyres = $290 each (approx) X5
Locker = Ask around for a price, possibly $2500 installed?
Armour = Ask around, TJM or ARB 2nd hand $500 for front, you could get sides made for around that mark also. I made my own for $130 and my time.
For about $5000 (in new gear) you can increase the performance off-road alot. But if you shop around and get good quality 2nd hand parts you can almost cut the price in half.
Hope this helps a little, just my 2 cents, others will hopefully have some better input!
Good Luck