Have fun...It is mostly a superb route.
Try and do the Liverpool - Hale part before lunch as there can be problems onec the local Yoof get out of bed and start hanging around, but we had no real problems.
The first part form Southport is fine, but Liverpool is a little industrial and there is a horrible set of stairs (- yes stairs) up from the waterfront just outside Hale, and watering holes can be infrequent (or evening only) so some self support is essential in case youi miss lunch.
The only other thing is be prepared to carry the bikes. Due to the love of mopeds (usually nicked) amongst the locals there are barriers frequently that are just the wrong width to get the bike across - lots of lifting and shifting.