Remember to bring your passport! You need to show it when boarding and leaving the ship.
The ferry crew are very accommodating to cyclists. There are good cycle routes to the Hull, Rotterdam and Zebrugge ports. Beware Rotterdam Europort is approx 20 miles from Rotterdam (Hull port approx 3 miles from City Centre and Zebrugge approx 10 miles from Bruges)
The cheapest way to get a ticket is to say that you are willing to share a cabin (Single was £45 in Dec). The cabins has 4 beds with an on-suite shower, its fairly civilised. Worth taking a bottle of water as far as I know there are no drinking water taps on board and the bar is expensive. There appears to be a disco Friday nights hand on the Pride of Hull the dance floor is at the centre of the ship (?). I got pretty much no sleep from Hull-Rotterdam. I’d recommend asking for a quiet cabin and avoiding the weekend break ships.
Booking over the phone you get a reference number and an email. You simply follow the cars and show the check-in your email and they give your ticket and a plastic strap to put on your handlebars.
You ride up a short ramp into the car loading bay and the crew point you to a place to strap up your bike. I left my panniers on my bike to save on hassle and locked it to be safe. The car bay is locked at sea and seems pretty secure. Worth packing a small bag for the night.
The car bay is opened shortly after docking and you can usually move to the front of the queue and be the first of the boat.