We stayed at the Hilton Hua Hin in November. HHonors Gold. Upgrade to a slightly larger room with a semi-Gulf of Thailand view. Breakfast is a really extensive buffet and provided to Golds. Other than that, no special treatment.
Re:beach. ??What beach??. A tiny strip of dirty sand behind the pool next to a dirty harbor.
Personnally, I would not go to Hua Hin. There are many places in Thailand that are far superior. Hotels are not Hiltons however. J.W. Marriot Phuket is outstanding. Dusit Island Chiang Rai is quite pleasant. J.W. Marriot resort in Bangkok is excellent particularly for $40 on Priceline. In fairness, many on this board love the Conrad Bangkok, I cannot comment having never stayed there.