Ok. Upbound you enter the navigable part of the old Galop canal just west of Cardinal. Downbound you enter the "North Channel". See attached GoogleEarth grab.
There's not much else of the old canal you can explore. The section from Cardinal to Iroquois is too shallow and full of snags for a boat your size.
If you need a marina there's one you can get to on upper side of the Iroquois Locks. See second attached GoogleEarth grab.
If you can unstep your mast
and your air draft is under 8' 6" you can get under the damn at Iroquois and not have to pay the Seaway locking fees
. That's the only lock that applies to though.
There's a marina along the old canal locks at Iroquois on the lower side of the dam. It's a nice spot. Plenty of deep water
Have a safe trip.