We usually do the Cairnryan - Belfast (Stena) route, but are considering Liverpool overnight this time. Are the Liverpool ferries as hideous as everyone says now they've been upgraded? We love the Cairnryan crossing, but live at the opposite end of the country, so it's a huge drive.
Other alternative is Fishguard, but I'm assuming it's a pretty long drive to Belfast (& on up to the north coast)
I haven't done many ferry journeys but have been on the overnight Liverpool to Dublin ferry a couple of times.
It's certainly not a luxury cruise, but the cabin was clean, spacious and comfortable. The route obviously caters primarily for lorry drivers as they make up 90%+ of travellers but there has always been a few people in cars
You got a free evening meal and breakfast (adequate, nothing special), and alcohol could be purchased reasonably cheaply (I seem to remember that you could get a bottle of wine for a fiver).
Worst thing was that they knock on your cabin door at about 4.15 am as they want everyone in their vehicles, ready to disembark at about 5 or 5.30 am. It is very impressive to sit on the car deck and watch the lorries parking up, inches away from each other and reversing up and down the ramps that are hardly bigger than them.
What about Holyhead-Dublin? It's max two hours past Liverpool to Holyhead (and all dual carriageway), then the fast ferry crosses in under two hours and you could be in Belfast in another 2. Might work out quicker overall.
DBoyfriend and I get the Liverpool ferry every few months to go see his parents. The cabins are nice enough, they've been tidied up a bit and the beds are comfortable. I'd imagine they'd be a bit of a squeeze for a family but nothing dramatic. Whatever you do, don't try and get away without a cabin, it's just not nice. And it's nice not having to use the main toilets which can sometimes be a bit grim. The staff are also the friendliest people ever, although DBoyfriend says all Liverpudlians are like that!
Holyhead won't work as we can't get a cabin on the sea cat & iirc the timings don't work well on the other bigger ferry (actually will check thinking about it, in case the ships have changed - our last Holyhead trip was one of the worst two hours of my life though & I swore never again!)
Yes we'd definitely get a cabin. We're leaving ds2 & ds3 at home so it shouldn't be too bad. We always get a huge cabin on the Cairnryan trip