From just outside Burnley to the outskirts of Leeds is the continuously pretty part although there is stunning scenery between some of the western towns. The locks whilst having heavy gates are generally well maintained and I wouldn't say excessively deep compared with the south. Heading east after Gargrave, the most northerly point, there are many swing bridges to operate, mostly manual which can slow you a little although a few are electrically operated. Some can be challenging solo but perfectly feasible. As suggested, Skipton is the jewel in the crown.
Not rushing excessively I've cruised single handed from the bottom of the Wigan flight to Skipton in six days. With two or more, hiring in the middle and avoiding the Wigan flight you should be able to cover most the the remaining canal there and back in two weeks.