From Pleasant Valley, having a car really is your best bet. It'll be more convenient in general and you won't break the bank paying for the gas.
Assuming you don't have one, the Dutchess County Loop Bus is your only other option without having to call a cab. Buses head from the east into here and then to Poughkeepsie at least seven times a day according to the newest schedules (and obviously, the buses run from west to east through PV as well) and it'll cost you at least $1.75 each way for fare. That would get you to the City of Poughkeepsie, but if your destination was somewhere like the mall(s), you'd have to get on another bus.
