200 days sound crazy, even for a highly complex scene.
Soft shadows(as Flak pointed out), volumetric lights, DOF, highres image based textures & transparency masks, glass and reflection all eat render time, so try applying what you can with postwork. It can save you weeks (or in this case, months) of rendering.

Perhaps you should also consider upgrading your machine if you´re going for heavy scenery. 3D require a lot of power from the hardware, and unfortunatly it doesn´t sound like your CPU and the amount of RAM will be enough if you need to speed things up.

One other thing i would consider is the resolution. 300dpi for a normal sized boardgame sounds like overkill to me. For most printing, 72 dpi and render resolutions around 5-6000 pixels is usually more than enough.
Unless it´s a very large boardgame. :)

Good luck.

Rudolf Herczog
Digital Artist
www.rochr.com