Training camps? Or at least for the majority of their careers. I know there was a road warrior type fighter who was all over the place taking fights constantly, had a really good record against pretty crappy opposition. Had no amateur experience and worked out in his backyard... Buck Smith? Peter Buckley? Someone like that. I know when Frazier was younger just getting into boxing he hung up a sack full of clothes and banged away at it. So what fighters had to resort to "dinosaur training"?
This is an interesting post/question that might apply to a lot of the ancient boxers. I don't know that Sullivan ever trained in a conventional sense to any great degree (although I think he did have a "trainer" that extracted him from a bar or two).... so those before him might not have either. I've read some of the guys from that era, and before used to "fight" tree bark. While the tree bark matter is probably apocryphal, it is entertaining. To be honest, I can't really give a concrete answer to this question. However, if one is interested in a lack of formal training, the old time guys are likely a good place to start, as you know.
