Junction City is a ways off I-5, but it's an easy (and flat) road. If you take the Diamond Hill exit off I-5 towards Harrisburg, you'll pass the old Safari factory which, after being acquired by Monaco, became the Monaco service center and main cabinet shop. I'm not sure what it's being used for nowadays since Monaco was acquired.
If, instead, you stay on I-5 and take the next exit at Coburg, you'll pass the old Monaco factory, with the Marathon Prevost bus conversion factory across the street. Pay a visit to Marathon if you don't mind drooling and can leave your check (cheque) book behind.
Junction City was home to the Country Coach factory, but I don't know what manufacturing is going on in JC nowadays. There's the large Guaranty RV dealership there.