My goal by the end of this year - or even better by next September - is to only owe $200,000 on our mortgage. I added up what we owe on both mortgages combined and it wasn't has bad as I originally thought ($210,000), but we still have a long way to go to get to "break even".
Main mortgage: $185,792.44
2nd mortgage: $22,993.7
Total as of December 12: $208,786.14
So I want to pay down $8,786.14 by next September - that would be approximately $1,000 additional principal each month.