1> The forum you posted this in is, as its name suggests, for tutorials or reference materials. If you have a question or suggestion, it goes in the main C&C forum. I'll notify the moderators to move it.
2> What you want isn't possible. It'd take a ridiculously large amount of work to get something even close to what you've described, until we get the DLL. Even with the DLL it's unlikely to be something we can do easily.
Currently the only way we have to let water units move across land hexes is to give them the promotion that ignores terrain costs, but a water unit with that promotion would try to move to whichever hex it wanted, not just follow a specific path of a canal. The Lua overrides necessary to keeping the ship from moving off the path would be tremendously problematic given the difficulty of evaluating possible paths.
3> Even if it were possible, the people who are capable of modding have their own ideas that they're busy implementing in their own mods. Asking someone else to make a mod for you is very unlikely to be successful because of this; learn how to mod for yourself, make an attempt at it, and then if you get stuck ask for more specific help. Although in this case, see #2 first.
If it were something that could be handled through simple XML then we'd have it done already, but since this sort of thing requires heavy Lua modification it's not something you're likely to accomplish if you've never modded.
