That's actually a great question...I've always meant to do just that but have never gotten around to it! One resource I've meant to look into further is
this site. It looks like it hasn't been updated since the tour ended, but it combines biking and tour-watching for varying lengths of time (check their reservation page for a list of options). I'm not positive on the pricing, but I imagine it's pretty spendy. One of these days I would like to do something like this, especially since I've grown as a tour fan over the years. If your boyfriend's a fanatic and you've got deep pockets he might be interested.
And if you do it, let me know what it was like!