If it were me, actually I've been in this situation, and my girlfriends dad is a regular blue collar kind of guy, I'd go with jeans and a nice button up with the sleeves rolled up and tennis shoes. I'd rather be able to easily associate with him than impress him with my smart loafers and matching pants and socks. It's true it's always better to over dress, but in this case I'd rather under dress, if he's a blue collar guy he'll be thinking 'douchebag' in his head over and over if you're dressed like you're going to a job interview. My recommendation obviously changes if you're in your 30's or 40's (I'm 26).
I agree 100%