Marketing Ideas for Multi-Family (4 to ~40 units)

[Dev Horn]

OK guys, help me out here. We're working on a new campaign for a large client, and they want to branch out into multi-family (4 unit multi's up to small apt complexes). Do you have any ideas about how to market to the owners of these properties? -- for example:

Are they found in the "absentee owner" lists (Listsource, et al)?

Or via data from the county or some other public source?

Would you send them something like a postcard or letter? What would be your value proposition?

Is it best to track these people down and CALL them (and send them direct mail)?

I'd love to hear from people that have had success in marketing to small multi-family in a competitive suburban market... or from YOU if you just have a great idea! Thanks, guys.