As already mentioned, there's quite a variety of terrain on this ride.
The first 50k is flat and fast, then there's a gradual climb up to the first control at Lake Vyrnwy. A good idea to feed up here as things get a little bit hilly from here. There's 2,500m of climbing in the next 100k. The scenery more than makes up for the effort though.
Most people end up getting to Llanberis rather later than they'd expected, but don't panic; you've done the hard bit and you can make up time on the rest. And you'll have worked up an appetite to do justice to the portion sizes in Pete's Eats.
Anglesey is not entirely flat, and is exposed so any wind can make it hard work. You're going the opposite way round this year which means you get to Holyhead slightly earlier and there's an increased chance you'll make it whilst the cafe at the supermarket is still open.
I've always found the A5 across Anglesey quite a boring road, straight, wide and through a series on nondescript villages. Which is one reason why you take the long route round the coast back to Menai. Another advantage of doing this section in this direction is the view of the bridge on the run into Menai.
A good target for most is to get to the control at Bangor Services before dark. We're a bit earlier this year though. The A5 is a great road for a night stage. The surface is good, you can't get lost and it's deserted. Telford engineered the road with a maximum gradient of 1:20, so it's all easy riding (Bangor Service to Betws y Coed is 25k in less than an hour even including the climb of Nant Ffrancon).
I'll be at Glyndyfrdwy at 345k to dish out soup, beans on toast and cakes to keep you going to the finish. There'll be camp beds and blankets as well if you're in need of a sleep.
It has been ridden in just under 17hours, but a more typical time is 24hrs. The weather makes a big difference though, as the outward leg and Anglesey is quite exposed. In 2007 it rained and was very windy (in Wales anyway, we had sun and ice creams in Shrewsbury). The first rider back was 21hours.
Note for vorsprung: remember shorts! I did note whilst doing the recce that Coed y Brenin does now have a (small) selection of lycra (non baggy) shorts.