In reply to marktrik: Depending on transport options, Hill Inn quickest if you have the option of transport. Take note of entry/exit point onto summit platuea, possible to end up heading to Horton but after 15 absolute max if you have the attention of a zombie, you'll realise your mistake. Just retrace your route and descend the right side of the hill. No probs in poor viz.
From Ingleton the Crinna Bottom route is quickest. TBH the paths are so well defined you have to try hard to get off route. Use a good dose of common and map and compass if conditions are crap.
How long it takes depends on you.
Have a good time, moonlight walks on Ingleborough are something special.