I added Harbor Freight waterproof cases to my Trail. The little one on the front is mounted to the Motoskill front rack. This was an easy installation since I just drilled through the rack and bolted the box on. Two bolts holds it very securely.
The back case is larger, the "2800" size they offer, and I bolted it to the G-Craft rack. I built a custom aluminum plate for the back of the box, then bolted the whole assembly to the G-Craft rack. After simulated drop testing, (laying the bike over onto the case), I decided there is no way that the way the G-Craft rack mounts using the two tool case mounting bolts and some loooooong extension bolts that it would ever survive a crash, or any sort of load. So I fabricated a brace that supports the G-Craft rack via the main rack (see pictures). Anybody who is using a rack that mounts to the toolbox bolts, I would HIGHLY recommend doing something similar. Now I'm happy and it should hold up, time will tell.
The back case is larger, the "2800" size they offer, and I bolted it to the G-Craft rack. I built a custom aluminum plate for the back of the box, then bolted the whole assembly to the G-Craft rack. After simulated drop testing, (laying the bike over onto the case), I decided there is no way that the way the G-Craft rack mounts using the two tool case mounting bolts and some loooooong extension bolts that it would ever survive a crash, or any sort of load. So I fabricated a brace that supports the G-Craft rack via the main rack (see pictures). Anybody who is using a rack that mounts to the toolbox bolts, I would HIGHLY recommend doing something similar. Now I'm happy and it should hold up, time will tell.