Whenever I stay in the cabins or one of the 1BR DVC units, I always tip an extra dollar or two over what I tip in a regular hotel room, as they have a larger space to clean and the kitchen to take care of. I think $5 sounds good for this type of accommodation.
Keep in mind that you don't have the same Mousekeeper every day. You will typically have one for five days and a different one for two, but if they get backed up from a lot of check outs, you may have a third one in the mix. So if you notice that you have great service, except for a couple days, or lousy service except for a couple days, this could be why. This is also why we tip every day, instead of at the end of the trip.