That's a whole lotta fiver for a 2500. I've got an 06 Dodge 2500 CTD and I wouldn't try to pull that rig. You'll most likely be overweight in all categories, payload, GCWR, axle ratings etc. I think that rig is going to need a one ton truck to safely pull it.
The tool box might work in that set up but it's gonna be tight. Probably going to depend on the dimensions of the tool box.
Kevin & Janine
2006 Dodge 2500 Megacab CTD 2WD
2012 Palomino Sabre 32RCTS
Pullrite Superglide 16K Hitch