No special access issues
1) Special rules at the crag:
Haad Sai Noi is a popular beach among weekend tourists from Bangkok. The beach offers amenities such as a couple of resorts, restaurants and guest houses. Be mindful of beach-goers, don't endanger them in any way and keep a low profile. While there is no reason why this beach should be closed for climbing, Thailand doesn't have the best track record and climbing areas have been closed without much warning and without any good reasons.
The mountain on the north of the beach belongs to a big temple that is ever expanding. Concrete walkways are built over boulders. Don't climb on temple grounds, stay on the shoreline as to not disturb monks.
The mountain to the south of the beach (as well as the beach behind it) belong to the royal family. It is completely off limits. Do not attempt to climb it or to boulder there.
2) How to drive to the crag:
From Bangkok, take a train (~4 hours), bus (~2.5 hours) or car (~2 h) to Hua Hin or Pranburi (slightly longer). Getting to Haad Sai Noi takes about 30 minutes from central Hua Hin or Pranburi.
From Hua Hin, take the highway south and exit at Khao Tao. Turn right before the big water reservoir and follow the road, keeping left, until you see a sign to Haad Sai Noi. Turn left and arrive after another 5 minutes. There is parking at the beach.
3) How to reach the sectors on foot:
Haad Noi South: Go to the beach, turn right. You will reach a lone block after 5 minutes or so.
For the other sectors, go to the beach and turn left. At the end of the beach you will find a small hidden path going up over the rock slabs to the left and into the forest. Follow this path until you are in front of Edge Case. Then keep walking further along the shore over the rocks to reach At Sea (which is visible from Edge Case) and Causality further back. Reaching Causality requires some scrambling over the rocks at the beach.