I am having much the same problem - one moment my imac shows up on the list then it's not there.
My imac is at my office localtion and I am accessing via my macbook pro. Both run Mavericks, both are set up with Back to My Mac and Remote Management is selected.
My ancient MacPro running Mountain Lion is the one machine that always shows up on my Finder list and is the least grumpy. (although it can have its moments).
Is Mavericks the issue here I wonder?