I found the tote I want to use so scrounged around for some other stuff and made this crude prototype of the "fish box" I'm going to make for the KLR just to get some idea of lengths, measurements and whether it will work or not. I think I'm going to forge on with this project.
I just used a single, solid piece for this trial fit, but the end product will have telescoping lengths of tube or pipe. Haven't decided what I'm using yet. The lengths of pipe/tube (about 8 or 10 inches long) attached to the rear rack grab handles with hose clamps will be a permanent addition to the bike. The pipes/tubes attached to the box will be of a smaller diameter than those on the bike and will slide into them and be secured with a hitch pin for quick release. When I'm not using it, I can just remove the hitch pins and quickly remove the thing, leaving only the two tube mounts attached to the grab handles.
Here's an overall idea of the concept:
Thought it might be an option for people who camp, allowing them to carry bulkier but lighter items like sleeping bags, tents, etc. Once you got to where you were going, you could just quickly remove it and go riding without it.
The problem with my current configuration is that it obscures the tail light. I suppose one could go with a smaller box or fabricate a kind of Z-shaped bracket that would raise the box up a few inches to where the tail light wasn't blocked. It's not a concern for me here since I plan to just use it for local fishing trips. This box is also large enough to provide another way to carry rifles in cases to the shooting range.
Anyway, it's going to be my temporary setup for times when I need to haul a little more on the KLR for outdoors adventures. I mostly came up with the idea to keep the KLR from getting all nasty when I haul fish home on it. That's a smell that doesn't quickly go away.
I usually take two rods, so on each side I'm going to drill a hole in the top front edge of the box and cut a notch on the rear top edge. That way I can slide my rod handles into the holes, lay the rods in the notches and have them projecting directly rearward where they shouldn't cause any problems as long as I'm on a road.
Thought I'd throw this out there in case anybody was interested in the idea. It's kind of difficult to carry larger fishing gear on a motorcycle and then get everything back home if you get into a Honey Hole.