the floor boards were replaced because of rust
Depending on how well the job was done their could be hidden rust, you will want to inspect the underside of the truck.
the fiber glass hood and fenders were on the bronco when he bought it so he isnt sure about rust on those or why they were replaced
No big deal, there is no rust there and never will be, I like fiberglass
This needs to be checked out by someone that has mechanical knowledge to see how bad the issue is.
there is a few bubbles of rust on the winshield frame and a crack on a rear panel seem that has been bondoed
No big deal there the windshields are rust magnets, they are easy to replace. I would suggest replacing it with the stainless steel windshield if it is in the budget.
he did rewiring but one gauge doesnt work and he isnt sure if its from the wiring or fuse or what not
Thats not that big of a deal
he said the ad says "c4? transmisson" because he isnt to sure whats in the bronco and thats what he was told
It's probably a C6 but either the 4 or the 6 is a decent transmission.
I still think it is a good price if there is not a lot of rust.
When you drive it make sure you let it run for at least 30 minutes, this will ensure that it is not overheating also make sure you are in an area that you can get it up to 60 MPH so you go through all the gears. Stop hard a few times. When you get out let it sit and run for a little while then look under the truck and behind all 4 tires to see if there are any fluids leaking.
I see in your profile pic that you have a young one. If the truck does not have a roll cage then plan on having one put in (about 1-2k) don't put the kids in that truck until you do. Make sure you have a cage not just the one bar over the drivers head. Judging by the pics it does have a cage but I don't know if it is a sport cage or a family cage, if it is a sport and you plan to put the kids in the back consider having it modified to a full family cage. Find out if it has disk or drum brakes, if it is drum you should consider having at least the front switched to disk. The big three safety items are steering, cage and brakes. The steering looks fine from the photos, their is a cage but find out if it is a sport or family cage, and you need to find out about the brakes.