I haven't stayed at that property but did recently stay one just a few Km to the south (Cher Resort).

From Bangkok (city, not airport) I pre-arranged a metered taxi for 2,000 baht with a driver I've used for ~ 5 years. We had one pick-up in Prawet, near the airport.

From this property we transferred to Hua Hin city via private car, arranged locally, for 500 baht, admittedly a bit on the high side for this journey. We liked the driver/car so arranged for him to take us back to Bangkok after a stay at Putharacsa Resort, we paid 2,500 baht, again with 2 drop-offs.

You can often find Bangkok metered taxis in Hua Hin looking for fares back to Bangkok (after having transported people to Hua Hin), in/around the area of the train station and Phet Kasem (Rt. 4/Main north/south road). These can be bargained to 1,500 baht.