Hi Mr. Blister,
I know there is a section on LDPs, but it comes under 'Links' which I've assumed to be links to other websites. I don't know if they are intended to be more than that?
Anyway, regarding Youth Hostels, I'd use them every time if I could. They are usually very friendly, food is wholesome and affordable, and many of them are now licenced so you can enjoy a beer after a day's walk. However, the first problem is that as I mentioned, the YHA have been closing down a number of those that are useful to walkers, and this is on top of those that were closed after the last foot and mouth fiasco.
Secondly, too often they are block booked by schools, who seem to think that anyone who isn't a teacher or pupil is a paedo, so insist on no-one else staying there. Thirdly, the popular ones are often fully booked, which means you have to plan your walk exactly, and can't deviate from that plan (like take a day off if you find somewhere nice). However if none of these apply then Youth Hostels are good.
What LDPs have I done? Well I should first mention that much of my walking has been abroad along sections of European GR (Grande Randonee) routes. To complete a GR is a little difficult unless you can take 6 months off work, but for example we did a section of the Pyrennees a few years ago.
But unfortunately I can usually only get a week's walking at a time (the significant other isn't too pleased about too many extended trips - abroad is OK as she can take a holiday in the sun while I walk), so have tended to do UK LDPs in sections. The ones I've done are the Thames Path ('cos I live on part of it), the Two Moors Way ('cos I love Dartmoor) and the Cambrian Way ('cos I love Wales). I've done sections of others (like the SW Coast Path) but not completed them. Incidentally, I did consider the Cleveland Way myself, but from the research I did it's a bit tricky without wild camping or taking long detours each day to get to nearest villages. I could be wrong of course, which is why I've suggested an LDP section.
Cheers, S.