Mods I would recommend if you're truly wanting to go "off-road" , i.e. something more serious than gravel. :
1. mud-terrains or at least aggressive all terrains - tough sidewalls are important because with 2wd you won't be able to avoid some pointy objects that you could with a 4wd
2. selectable locker - 1 tire w/ no traction versus 2 w/ some traction - #2 better

- a locker allows me to avoid even needing my 4wd in numerous situations
3. winch - particularly good when going solo
4. hi-lift and other manual recovery gear - really hard to make this stuff not work
5. lift - might not need this and nothing too big but clearance is just one more thing that will make your truck more capable plus most aren't overly pricey for 2wd's
6. and most important - common sense - 4wd often times just affords you the ability to "play" a little, so if you can identify your limits and stay within them you'll be able to avoid many of the situations that will get you in trouble
There's a few more I'd suggest for specific terrain but that covers the basics for improving the general capability of your truck imo.
I've never owned a 2wd, but I've done a lot of stuff while in 2wd so I figured I could post. Have fun finding out what she'll do!