Took too much kit!! Really a lot depends on the weather forecast and how much you are prepared to tough out maybe four or five hours of semi-sleep. Apart from the first two back most bivvied somewhere between Fleet Moss and the start of the BW from Dent to Ribblehead. I bivvied on the Pennine BW before the descent to Newby Head. Where you bivvy will also depend on the weather: last year it was warm & humid so you really didn’t want to be somewhere sheltered near vegetation because of the midges. Equally it was forecast to start raining overnight so being up high could also have backfired (it actually began to rain at about 6am).
A lightweight inflatable mat like the Klymit x-frame, a down summer sleeping bag (PHD) and a bivvy bag (Alpkit HUnka) will weigh under 1Kg but could cost a significant amount of cash 😆
You are allowed to use (but not pre-book) any facility you find on route. Last year most tried to get to the Dales Bike Centre before it shut but that might be a bit harder to do this year as the new route adds about 15Km before you get there (comparing the two route maps, it is 15Km shorter in the latter third)