On Day 4 (Check in is Day 1), you will have a full housekeeping service. On Day 8, you receive Trash & Towel service. Then the cycle repeats (On Day 12, you get full hosekeeping and on Day 16 you get Trash & Towel, etc.)
How wonderful that you can stay that long. I would recommend uploading Caskbills DVC Planner, when you print out your vacation plans it will tell you when full housekeeping and trash & towel service is for your vacaiton. Here's the site: http://web.nalu.net/~wneth/dvcplanner.htm