My picks....
1- CSR; The grounds never seem too crowded, there are relaxing hammocks in the Cabana's section, and the quiet pools never seem very corowded. The main pool is not usually too crazy either.
2- POR; great quiet pools, especially in the mansion section. The grounds are very relaxing and there are alot of nice walking paths.
3- POFQ; Smaller and cozy, with nice quiet and romantic walking areas in the evening. The food court is usually pretty hectic as is the inner courtyard pool area. no quiet pools.
4- CBR; Nice resort and can be quiet if you are away from the main building and pool.