It's certainly possible to do light or credit card touring on a modern road bike by using a large Carradice sadlebag (Camper or Nelson Longflap) and a handlebar bag. If you go truly minimalist and use bubble wrap as a sleeping mat, eliminate cooking equipment and use a tarptent you can probably get by with just a saddle mounted support for the saddlebag and no other racks. I credit card tour with a saddlebag and a handlebar bag on a Rambouillet as it is a reasonably light bike with good tyre clearance and comfortable all day long.