If anyone lands here researching the same topic i can now speak first hand. This is a very delayed update as I rode it as planned in mid September, but based on comments above opted for the full suss 29er (most definitely the right choice). I had 3 and half days of the most amazing blue skys, with half a day of rain to keep things real. The route is, as the posts above suggest, old school. There’s plenty of hike-a-bike in the lakes, and a bit on the moors as well. I rode it in reverse as the NY moors was home ground and I wanted to finish in the lakes. I rode solo over 4 days/3 nights, stopping in Osmotherley, Brough Sowerby and coniston. The first day was the hardest mentally, with the 10hr days seeming normal after that.
It will be either King Alfreds Way on the gravel bike or the Great North Trail on the 29er next as I’ve got the bug for multiday long distance rides.