I vote for Bob or maybe if you could find an extrawheel trailer. Or hell, even just a cheap kids trailer off of CL. Give the bearings a good tune-up, get some decent road tires(low/no tread) and go ride. If you don't need all of the parts, take them off. Personally, I'd ditch the canopy/cover part for less weight and better aerodynamics. Your current bike, especially given your weight, isn't going to be great for loading a ton of crap onto a rear rack. Even if the rear wheel doesn't fail, it's gonna handle like crap.
As mentioned, cat litter buckets have been used by many as a cheap, rugged(more than panniers), waterproof system. A small kids trailer, stripped down, with a couple kitty litter buckets laying down on their sides for less wind resistance. That would make a great, Cheap set-up and not reduce the handling or reliability of your bike.
Edit: Random idea that just popped into my head - Completely strip the kids trailer to frame and wheels. That's the least weight and most aero. Then get some heavy duty shock cord and tightly weave a hammock onto the trailer frame. Put your buckets/dry bag on that with a bungee net over top to hold them down. That will provide some suspension so that your stuff isn't banging and bouncing around if you hit some big bumps, pot holes, on and off of the road edge, etc.
Last edited by 3speed; 07-13-19 at 02:24 PM.