I believe the oil drain bolt takes a 17mm socket.
Identifying what tools you want is really based on how much stuff you may want to attempt while on the road. Changing your oil on a long trip can be handy.
For example, to remove the body work, you would need a 5mm or 6mm hex wrench/socket, a Phillips/JIS screw driver and an 8mm wrench. To rotate the fuel tank you'll need to add a 10mm and 12mm wrench (you'll need 2 10mm wrenches to loosen the rear fuel tank mounting bolt.
If you want to be able to remove wheels or brakes, then you'll need some additional wrenches (some of considerable size). The list of tools can start adding up in a hurry.