shobbaker.
The coast road will be very busy and you will only get part way to Southport before being turned off. I really don't know what to suggest but you could try the A59 to Ormskirk when you leave the M57 i.e
towards Preston. It isn't far and then you could go to Southport and use the Park and Ride as above. Good luck. I'm off to Canada so I'll give it a miss this year.