I posted a message last week after using mapquest - there are 4 parks along I-5 in Salem - I also posted a link to the map to see if anyone knew anything about the parks - one is right off Rt 22 just west of I-5 and it looks to be pretty large - I just don't know anything about any of them since I don't live in Salem, probably any of them would be fine and all are within a few blocks of an exit from I-5.