With my uncoated carbon steel knives I take off the handle slabs and put a layer of grease underneath to help prevent rust. Then I put it back together and wipe down the rest of the blade with an oil-dampened cloth. For an uncoated blade, this needs to be done somewhat frequently, at least until the blade builds up a nice patina from use.

Now the RSK Mk2, on the other hand, is powdercoated; which should do a pretty good job of preventing rust everywhere that the powdercoating is covering the steel. For the most part, you'll only have to worry about the uncovered areas.

Therefore, you'll have to look the knife over, see which areas go down to bare metal (like blade edge, maybe lettering, maybe holes in the handle, ect), and make sure to pay special attention to those areas. How often this will need to be done depends on what the knife is doing and where it's doing it.

For use around salt water, you might need to wipe down those bare areas at the end of every day to prevent rust spotting. For a desert trip, you might only need to wipe it down when you get back home. The biggest issue is keeping it dry. A wet sheath, for example, is a great way the rust the heck out of a knife in just a few hours.