Great advice from everyone!!! Items like the tailgate, doors, front fenders, and hood are simple bolt-on jobs. The parts of the cab and cargo area will require some welding whether using a patch panel or full replacement. You will also want to look underneath at the floor pan and bed area for any rust or cracks. If you have carpet, pull it up to look for rust. If you have rust-thru from the outside in a panel, there may be more rusted metal under the paint.
If you have absolutely no experience with a welder or cutting wheel, you might want to leave that work to a good "body man". Smoothing out the seams of the welds and working with body filler takes a little practice, and just Bondo will not work to cover holes or rust. Aftermarket parts do not always line-up with the original panels, so you may need to trim or fit them to work. You might want to try a small part, like a rocker panel, so you're not out of alot of money if you mess it up.
It really depends on what conditions and purpose you have for the Bronco. If it's just a trail rig, you might get by with patching or just cutting away some spots. IF you want a show-quality ride and you're going to spend a few grand on paint, it's worth the money to have a pro do the work.