You will be amazed how well this truck does stock. Having said that, by putting on a more aggressive tire you will improve performance. When I go off roading I put on my Mud and snow tires. they are 225r75 two sizes bigger than stock. This gives me an inch or two more clearance. In some cases you may want to air down. This affects my mileage by about a mile per gallon.
You can go to 235's on stock rims but you may have to trim the fender flares
The sporty is rather articulate and can fit in tight spots. Crossing a river or stream is fun and can be done stock. I've had water up to the windshield many a time. I don't have a snorkel. Caution must be used as you have a limited amount of air under these conditions.
Do you have a stock roof rack? I'm assuming you don't. The stock can easily hold the 150lbs
A come along as well as a high-lo jack as well as a strong tow strap will do you good service instead of investing money in a winch.
Check all your fluid levels and if you have the wheels submerged for any length of time you may need to repack the front hubs.
When was the last time your timing belt was changed? I think the 98 is OK if the belt breaks. Earlier models had problems and would do valve damaged if the timing belt broke.
Is it the manual warn hubs that you have? They are the most dependable. I have mechanical automatic hubs that work extremely well.
Your in for a lot of grin time when you find out how versatile this beast is.