Hey, I'm sure others have useful feedback, and you seem to have done your research. Camping at Bowen Ranch :: There are no sites, like a real campground. Its not formal like that. There are a couple of picnic tables and fire rings set up here and there, on this hill or down in that valley, all around the parking area. On any given weekday night, you could be the only one there, or maybe there will be 2 or 3 or 4 campsites set up whenever you want to set up. On the weekend, I'm remembering a Saturday morning in the spring, I showed up and saw like 60 people camping all over the place. There really isn't room for that many, but you can spread out, and set up anywhere in the land nearby. Speaking frankly, the campsites at Bowen are not really cleaned, and there is a problem with trash and glass and such in parts of the area. If Bowen is too crowded, or the parking lot not attractive (I've camped there many times and you can find nice places there - my fav spot is down in a little valley below the parking, there is a table down there), I would recommend hiking on the trail down the first big hill, crossing the dirt road and setting up off that road just before the main trail down to the hot springs starts. Often people will camp there, especially if they can reach it on that dirt road with their 4x4s.
I have never camped off the Bradford Ridge, and you are at higher elevation on that trail before the last descent - so yeah, maybe bears? Surely not on the Bowen side.
Road to parking at Bowen - it's been improved, last year, and is fine now for basically all cars. Enjoy!