I place my 3000 in the bed against the cab on the passenger side with the plug facing the passenger side of the vehicle with about six inches of clearance. That way, I can reach over the bed and plug in an extension cord that will reach back to my FW cord.
To lock it very securely, I use a very heavy chain, and a really stout padlock. I run the chain over the handle, and clip the padlock into a tie down loop that is in the front right corner of the bed. The weakest link in this set up is the Honda itself. Someone with a hacksaw could cut the handle pretty quickly and haul it away.