The key is to have the gin pole, and the mast stayed. I use 4 tie down straps. 2 on the mast (I attached some padeyes about 6 feet up on each side), 2 on the gin pole. If something is leaning to one side, I just tighten the opposite strap. My mast is mounted to a hinge plate from Dweyer.
This is very useful information Kenr. The hinge plate sounds like a great piece of kit for a boat that is going to be trailered. The mast plate, combined with a forestay quick release could make a boat with even a poorly designed mast stepping system into something decent. It won't break the bank either. I do have one 18.5 foot sloop that is basically a give away that I have had my eye on for this trip that I have been avoiding because it doesn't have a pin on the mast, a mast plate like this might make all the difference.
If the OP is OK with an 18' boat, he might consider an 18' Marshall or 19' Menger catboat that is set up with a mast tabernacle.
I love Cat boats, especially for sailing short handed in very confined waters. So far, I've only spotted one within a decent drive for me and it has no cabin and is lots of $$. But if anybody knows of an 18 or 19' cat boat in Eastern Ontario at an inexpensive price, I would be interested in hearing from them.
The only minor thing I can offer to what others have said is that working from a belay point across the dock on the opposite finger helped a lot although obviously required a longer line....
...The idea of raking the mast back is a good one, but not as easy as it might seem. A friend of mine has a 60' ketch (yes much bigger). I don't recall the air draft - 76' I think. The boat is rigged to lay the main mast back to fit under 65' bridges on the ICW
...You'll have a great time. It sounds like a great plan.
Cool idea about using belay points ashore, I have been trying to think of different shore features I can use to facilitate my mast situation. There are several marinas along the way with mast cranes, and every bridge either has it's own tie up wall or a tie up wall in close proximity (45 locks in 125 miles).
Your friend must have nerves of steel messing around with a 76' mast. Good for him.
I think it will be a good one. The canal was built as a military transportation route to carry troops and military supplies. The entrance to the canal is protected by a large 19th century stone fort and several Martello Towers. Along the way are several 19th century fortifications, military settlements, towers, etc. The fees for all of them have been waived for 2017 (might be a bit busy). Plus good fishing and lots of pubs and eateries along the way. Lots of neat old mills, provincial parks and conservation areas too.