depending on where you are, you can use nj transit train from princeton jct (west windsor). the only other buses from there (i think) are local routes to new brunswick, princeton, princeton junc., perth amboy and trenton. if you look closer toward princeton junc, you'll find the avalon princeton
Avalon Princeton Junction, West Windsor - Trulia which starts at $1380, and has a pool and a fitness center. plus, it is a 4/5 min drive to the princeton junc. train to the city. and, the 612 bus stops outside avalon and runs to the station. since bus is included in your nj transit month pass, you won't have to park at station (
http://www.njtransit.com/pdf/bus/T0612.pdf). and to drive to king prussia, you just take rt1 south to trevose and take pa tpk.