Hello John. Do you have a rental history for your second home, either long-term rental or vacation rental? Your post states that you are in the 98250 zip code which includes San Juan Island. The San Juan Islands are a wonderful vacation destination (as well as a great place to live) and vacation rentals here can be a great way to add investment/income value to a property. There is a pretty good long-term rental market here on San Juan Island as well. Once you can establish that your home can provide an income flow, via either long-term or short-term rentals, it should be possible to market it as investment property. There are a couple of very good long-term and vacation rental management companies in Friday Harbor, including Windermere.
Are you trying to your second home into an investment property before it sells? Maybe you're hoping that would be nice selling point? Hmm...I would thing that you'd need to prove good renter history and show that the rent you charge would compare closely to the buyer's monthly mortgage payment.
J, I think this is an accounting/tax issue and you should seek advice on any filings or paperwork that needs drafted. Get a free 30 min consult to start with a tax advisor and if it is still unclear seek out the same with a tax attorney. Good luck.