[Updated 20 Sept, 2014]Ferry went out of business.[End update]
There are several ways to go between the two towns without passing through Bangkok and it’s traffic. Ferry runs 3 times a week. Big buses pass through both towns on routes that generally follow the coast of the Gulf of Thailand. The boat didn’t run on the day we wanted, the big bus passes through Hua Hin at midnight so that was a no go.
Last option was a minivan route that starts and ends in the two towns. Took it from HH to Pattaya, the trip convinced me to come home via Bangkok.
What happened? Van was at start point when we got there 20 minutes before scheduled departure time. Didn’t leave until 25 minutes after the scheduled time because he was waiting for a single passenger. A Thai, of course, can’t imagine they’d wait for a Farang. The driver avoided tolls by leaving and rejoining the toll road. That probably wasted a half hour, though we did get to see a bit of the countryside. Finally, the drop off point was not the one stated when we purchased the tickets.