So that leaves the foredeck or a tow. Towing might be reasonable in sheltered waters for short distances. I would never try to tow on a multi-day offshore passage. That leaves the foredeck. Not a great place. It is in the way every time one goes forward, e.g. to anchor, set up the whisker pole, set up or douse the asymmetric spinnaker.
A more critical problem is that it takes a beating in high seas going upwind. That green water across the deck is bouncing off the dinghy. It needs to be very secure. Over time my system has evolved into the setup in the pictures below. The stern of the dinghy is attached by two crossed straps attached to the stern of the dinghy and the deck. The center is held down by a tie down strap. And the bow is held down three ways: the painter and two diagonal lines to either side. These lines help keep the bow from shifting sideways.
This works well with one exception. The lee jib sheet tends to catch under the dinghy. It is thus important to assure a clear run before tacking or gybing.
Fair winds and following seas :)