slice that sucker open.
If you are half way comfortable doing inside outside patching you should give it a try. Running a one chamber boat is bad news for many reasons listed above as well as many more like the boat/frame/gear becoming a hazard for years.
Older hysides had some of the best material out there with hypalon coating an both sides. the stuff is bombproof. I have seen several of them in the shop that have been worn through the outer coating and the scrim(base fabric) and are still holding air. Dont give up on her yet.
Worst case scenario is that you cant get the baffles completely sealed and they leak a little, or you find that they are toatally blown and you patch it back up. At least it would give you a some time to get to shore in the event of a gash.
Most hyside baffles i have fixed have just been unglued at the top under the frame chafer where the sun bakes on them most. It is unlikely that a well constructed 80's boat with material in good shape has fully blown out all the baffles. Even if you could just fix two you may end up with a 3 chamber boat in the end. One baffle may still be intact. I would start with the ones in the middle of the boat as they are the most common to give. Make a slice in the boat big enough to get your hand in few inches away from the baffle and running parallel to it. Reach in and feel around to see what you are dealing with. If the baffle has fully come apart it may be a lost cause, as that is major, but i'm betting it isnt. Put a small light in there( headlamps work well if you can get them positioned) if you have one and you can look in as well. Glue her up and see what you get.
Inflate from the other side after a day and see how it holds. reach in and feel for leaks. If you find leaks, add more glue, rinse, repeat.
Anytime you are working with glue in general and especially when working inside a boat, wear an organic solvents respirator and safety glasses. The fumes will blast out of the hole every time you open it and your face will be right there. The more ventilation the better.
The bladder idea isnt a bad one either but i would try the baffle repair first. If you find that they have completely come apart instead of just separated from the tube the bladder would be a good way to go.