Why Did This Guy Do This?

I live in the SF bay area and I was visting someone in south SF the other night for the first time well I stayed a little late and as I got to the bart station I saw the last train pulling off. Well I then called a cab but it was going to take 30-40 minutes to get me. Well while I was waiting this guy asked was I stranded I said yes so he offered me a ride home. He told me that he didn't want to leave me there by myself with no one else around. So he drove me all the way home 75 miles and i had him drop me off about 8 blocks away from where I live. I offered him cash but he refused to take it. He also gave me his number and told me to call him up when I get a chance. What could this guy be up to and should I be really careful about this?