I rode the stretch couple of years back on a mountain bike, all 127 and a quarter miles in a day.
Had a large bike frame bag for water and a rucksack for supplies. Only made one shop stop on Burnley's straight mile where Tesco's petrol station is conveniently next to the canal. Had slightly slicker tyres on (continental double fighters) as found these gave adequate grip and comfort for tow path but have much less rolling resistance than the usual nobbly mountain bike tyres.
I'd recommend a couple of things for those wanting to do the route, definatly have a bell to let others know your coming. Pick a weekday ensuring the schools aren't on half term or anything so the path is as quiet as possible for you. Pick a day where it perhaps rained a couple of days earlier so the ground is a little bit softer, when tow path is rock hard I find it zaps your energy quite quickly being bumped around so much etc, but only light rain, mud is not your friend here and best to have at least a rear mud guard as whatever the weather water does collect at various points. A day when it's cloudly will mean less walkers venturing out and you can easily stay cool when riding, not sweating like mad in the sun using excessive water etc. Wind commonly goes west to east why most people choose Liverpool to Leeds direction.
There are two tunnels, Gallow and Foulridge, both of which require you to deviate from the towpath, ensure you know where these are and where to go beforehand. Also worth checking if canal and river trust are working anywhere on the canal as parts of the path may be unexpectly blocked and closed.
Is a tough one, not to be underestimated given some of the terrain, some parts are smooth such as Wigan, some parts are literally grass tracks, narrow or have tree roots everywhere but all is rewarding, and fun

I regret two things, not taking quite enough food so was running on empty last 20 miles and not taking a light as had more than enough daylight hours for ride so chose not to carry the extra weight but because of a crank issue had to stop numerous times and tighten / align the crank arm causing delays, ended up nearly cycling in the dark near the end, not exactly street lamps or anything on the canal lol, expect the unexpected.
Good luck to anyone going for it, are markers on the whole route so you always know how far to go and canal is home to a lot of wildlife etc. Geese or ducks may suddenly just jump out in front of you, or chase you lol and a lot of low bridges where you might meet other walkers. One not to be a crazy fast time trialist and just enjoy the ride is what I'm saying

Best