The road up North is passable day or night when it is dry. Just remember at night the insects can be bad enough to carry you away. When it rains, it will take twice as long to get anywhere, if you can make it at all. Lots of mud holes and you will get stuck.
I just talked to the owner of Island Ferry. The ferry has late runs North at 11:00, 12:00 PM and 1:00 AM. If there are four or more people, they all travel at the regular rate depending on how far North they go. If there are less than four, the rate is based on a private ferry. Belizean Shores is $50.00 BZ for a private. After Journey's End the rate goes up.
Belizean Shores is a great place. My wife and I used to own a condo there before we moved here full time.