Mike, hi. I’m no expert but no-one has answered so here goes.
There is some discussion here: https://wayfarer.org.uk/forum/topic/best-wayfarer-version-for-cruising/
My wife thinks we should get a Mk 4 (we have a 1A) because it would be better for cruising but I reckon that the way that it doesn’t have bilges, (so any water is among your camping stuff) and turns turtle more easily on a capsise, means that its the wrong answer. I am sure many would agree with her, or have another opinion.
More to the point I reckon that every mark of wayfarer has been used successfully for cruising, so its not critical either way. I’d focus on getting a solid boat. Here follows some advice based on getting it right and wrong with various boat purchases: Check the rudder fittings inside the aft boyancy chamber really carefully, all around the centerboard case and the support for the mast foot. Those are the three areas that are under the most pressure and go wrong most often. Look along the hull and check it curves as it all. Look along the mast and make sure it curves as it should. If the hull and mast are right you can sort anything else without too great an expense. It is likely that all of the above is fine – by modern standards wayfarers are fairly heavily built, with a fair margin of strength.
But, if you’re going to trail the boat anywhere then spend as much time checking the trailer and trolley as you do the boat. The consequences of it all going wrong at 60 mph can be dangerous and expensive. Check the trailer is strong enough (look underneath for rust), do a visual check for all bolts, look at the welds for cracking. And, above all, check the tyres and the wheel bearings. When you first drive it, stop after five miles and again at twenty, and put your fingers on the outside of the bearings. If they’re getting hot thats an indication of problems. Also look at the legal requirements, which are actually fairly sensible – the lighting board, the emergency breaking cable etc.
I very much apologise if I am teaching you to suck eggs. I am sure you could teach me much. I wish someone had told me some of the above a few years ago.
Good luck! Andrew