Hi Dave
Sounds like you are local to me, if you fancy a spin out give me a shout.
If you know what it’s like to Wigan, then be prepared for it twice and bad up near Skipton.
when I rode it 2 years ago the draggy grass really lowered my average speed and affected my overall time.
Wait until the route past the Blue Elephant near Wigan is completely dry then you know the rest of the route should be a a lot easier.
South of Blackburn watch for where the tow path crosses the canal with a foot bridge, this is easy to miss and you end up going up a dead end canal.
As for the bridges, my advise is while you are waiting for the route to dry out, throw your bike in the car and go and reccie the route around the tunnels, it will make it so much easier on the day of your big ride.
Rather than carrying lots of water, about every 20 to 30 miles you should find a locked tap for boaters to use.
Buy this key (but test it before you set out) to get fresh tap water along your way
Click here Canal drinking water key