Haven't been on the Lagoon 45.. If it is 4 cabins and 4 heads, then I'd say it would be great. 4 cabins and 2 heads? I'd personally look for a different boat. I'd suggest looking a range of boats anyway - they all have something different to offer with a wide variety of layouts.

And April would be a great time to go. We've been in a wide range of months and they've all been great. Jan/Feb/Mar when we've been was a little cooler - I actually like it on the warmer side where you just want to jump in the water to cool off - then again I also like having A/C on the boat Haven't been in April but we did go in May one year and it was a great time. Even got to see some of the poker run.