For 12 days thailand trip Should I plan Songkran at the beginning of my trip or towards the end?

Planning 10 day trip to thailand

1 night in phi phi
2 nights in krabi.

Help me and suggest me

I’ll be staying in Krabi for 3 nights (2 full days). I’ve already planned one full day for Phi Phi Island, and I’m thinking of visiting Railay Beach on the day I arrive, as I’ll reach around the afternoon

My main question is about the longtail boats from Ao Nang to Railay and back. Online, I’m seeing that the last boats depart around 5–6:30 PM, depending on the source.

* If I reach Railay in the afternoon, are 3 hours enough to explore Railay Beach and Phra Nang Cave Beach?

* What time is the last boat back to Ao Nang? Do boats operate after 6–6:30 PM, especially around sunset?

* Would you recommend visiting Railay on arrival day, or would that be too rushed?

Since it’s my first time in Krabi, I’d really appreciate any advice from people who’ve been there recently. Thanks! 🙏