Not only no lounge but the afternoon drinks and snacks for SPG elites were axed when Marriott took over years ago along with all the other SPG resort lounges as lounges at resorts are not Marriott brand standards. If you want a lounge at a resort then join IHG and stay at ICs or Regent resorts.

We booked a private car transfer from Bangkok to Pranburi. I suppose you could take the train to Hua Hin and get a Grab or something but I assume you're not penniless so you'd rather just get there. Plenty of private car transfer services in Bangkok to do this trip for you.