Hi mcraig :o)
I think just by hanging around him when you are on your visit and the fact your sitting with him whilst he drives may make him realise that you like him.
Laugh at his jokes, take an interest in what he is saying even if it is something you don't like or have no interest in and know nothing about, he may ask you along to one of his interests or hobbies which could be the start of getting to know each other on a one to one basis.
If for example he says he likes going to the cinema, you could say that you don't get to go that often which is a shame as there have been some really good movies on lately that you would have liked someone to go with to see and just see where the conversation takes you.
Also hold eye contact with him just that little bit longer (except if it's when he is driving!) and give him lots of little smiles (as well as big smiles)
Good luck and enjoy your visit and I want an update when you get back!!!! :o)