If you come for just beach and sun then you do not need to rent a car. Everything will be at your front door. To see mount Tide I would recommend to buy a guided bus tour. It is most convenient option to get to the cable car station at the foot of the Tide peak. You do not have to be concern with the parking it will wait for you if you do decide to go all the way up. Bus tours usually go with scenic route and stop on most interesting places on the way up and down. To get to Siam part and Siam shopping mall you can get a dedicated Siam bus which stops just outside of the apartment complex. AuquaPark is within walking distance.