The A583 between Preston and Blackpool is OK for a group as it's largely either dual carriageway or wide single, with a 50 or 40 limit most of the way.
If you want a quieter / scenic route consider going slightly north of Preston and coming through Woodplumpton, Inskip, Elswick and Singleton - or stitch together a route on the minor roads in between that route and your proposed one (perfectly possible, but signposting isn't great round there).
If you're happy with the route you've proposed, I suggest leaving the A583 at the traffic lights just before the M55, head down Whitehill Road, continue down School Road, right at the end onto Common Edge Road, left onto Squires Gate Lane and join the promenade at Starr Gate. You arrive in Blackpool on a much more pleasant route that way - the town centre's not a nice place to cycle.