I stayed there for a weekend a few years ago. Its a nice site, different areas with around 10 tents in each. Main shower block was great, but we were a little far away from it to be comfortable.
Boats can be stored next to your tent. The slipway is made up of rocks, pebble and shingle, I would suggest a 4x4 would be needed for a decent sized boat. Access to the water was tidal, I think we managed HW + or - 2 hours.
The Llyn Peninsula and Angelsey are fantastic, some of the best boating in the UK, about 10miles south is a really nice bay and the Ty Coch pub, well worth a visit.
Be carefull on the entrance, the lane is narrow and it has some really sharp bends in it, I took a 20ft boat and only just got round them.
We were happy with the place and will probably go back when we have time.