Hi John,
I don't know if this will help in your case but in Napoleon I wanted British naval units to be able to move from the English isles all the way into the Mediterranean.
I did this be creating a series of naval "zones" each within the typical range of naval units . At the beginning of each turn, any naval unit located in a specific zone received a goto command to move to the next zone down the French, Spanish and Mediterranean coasts.
From my personal experience, this appeared to work relatively well.
If you are interested, you can look at the following section in my event file (particularly the British naval commands):
12. AUSTRIAN, BRITISH, OTTOMAN, RUSSIAN and SPANISH MOVETO COMMANDS
I hope this was useful to you.