Skegness is my home town and have fished it from the age of 7 for a long time! having moved to Durham about 15yrs ago.......... Unfortunately April is not the a great time, some years if there is a good spring run of codling April can fish well with some mixed bags but to be honest it has been a good few years since there has been a good run! If there is a long spell of high pressure and settled there is a chance that some early hounds and always an odd thornback will show. If it has been warm and flat for a week or two then crab is by far your best bet as it will pick up hounds,Rays and codling they will usually be picked up at distance but sometimes will be found close in, bass do show all year round but are not prolific usually picked up targeting other fish, if there has been some sea on and a bit of north / north easterly on it then yellow tails and crab with a bit of squid will give you a chance.
If you plan on fishing straight off the back of butlins then it will mostly be flounders and dabs, lug for the dabs and crab for flounders, as the tide floods from low up and the gullies fill very close in at times 20yds. Hounds do show there but usually May onwards. I would recommend heading north of butlins, any where from trunch lane at Chapel St Leonards north to huttoft car terrace, lots of free parking straight through sand hills and onto beach, a bit like druridge bay.
Hope that helps
Cheers dave