Just thought I'd post to say that on Friday I "ran" the Welsh 3000s, after much posting looking for advice on training, kit, route and every other aspect of it! Thanks to everyone who gave advice.
I set off at 4:30am from Pen Y Pas, got to Snowdon at 6am, got to Foel Fras about 5pm so 11 hours "peak to peak", took several more hours to get back to the car at the Aber car park next to the A55, so 14 hours all in door to door. The whole route was about 52.8km with 3,944m of ascent.
Weather was mainly cloudy with relatively little visibility, but there were some points where it cleared and you got a nice view and a bit of sunshine to break it up.
It definitely felt like a run of two halves - gruelling up-hill trudges but then pleasant running across the Carneddau. A lot of the first part of the route was scrambling or too rocky to run on as well. I can't begin to imagine how the record times are set that are sub 5 hours!
I carried all my food, spare layers etc. in my running pack, re-filled water twice from streams. Was very fed up with gels and Clif bloks by the end of it.
Legs were getting cramps by the ascent up to Glyder Fawr so I had to be careful not doing too big steps up from then on because I got cramps several times which stopped me in my tracks.
I was still running by the end so it was definitely the height gain not the distance that killed me, but I probably only ran 1/4 of it.
I can't say the experience has made me desperate to do more mountain ultras, but my legs are still very sore so maybe I'll feel differently when they're better!
Now I've finished my goal (and training programme) I'm wondering what to do with my new found fitness before it ebbs away, or wondering how to maintain it without such a demanding training programme. I thought I might go for a flat marathon PB, or try some longer routes in the Peak District like the Derwent watershed etc.
Annoyingly I was using my Garmin Fenix 6x for navigation and after less than 1/3rd of the way in the watch had gone from 100% charge to about 65% charge... but it's advertised as having something like 60hours + GPS battery life. So I had to watch it the whole rest of the route and every time there was an obvious path or I knew the exact way I was switching it to ultra trac mode with longer battery life, by the time I finished the watch had about 14% battery life. Really annoying and a clear lesson not to rely 100% on technology.