Curt,
Nobody has replied here for a while...I gotta tell you, it's like this: if you build a house, do you want carpet or hardwood floors? Do you want electric or gas burners in the kitchen?
Modifications overwhelmingly depend on what you want your Bronco to be able to do combined with your personal preferances.
As far as towing a Bronco, keep in mind that they approach 6,000 lbs...I would recommend using a trailer with brakes. This would also keep from wearing out your Bronco drivetrain and keep you from having to disconnect the drive shaft and stuff like that.
A good running and driving stock Bronco with aggressive tires will take on a lot of trails. There's probably a formula somewhere for tire size and horsepower required for competition, but for most casual wheeling a good running and dependable stock rig does just fine no matter what the current 4wd magazines lead you to believe. I have been all over Colorado in a 4-cyl CJ5, got pictures sitting at the top of Engineer Pass at 13,500 ft - no mods on that engine.
Anyhow, please don't take this post as a negative, it's good to have you in the Bronco owners club!!
If you can offer more specific requirements then the folks on this site will definitely be able to help, I have learned tons and feel humbled to be able to offer advice from experience every now and then. Let us know how it goes.
Good luck,
Brian
