I would also suggest being strategic about the timing of the increase as others have stated. 

Turn-key rental acquisition teams also exist for investors who want to own hands-off properties in strategically advantaged locations.Your research process will likely have two phases. 1) Gain an understanding of all of the structural options available that meet YOUR specific financial goals.2) Develop acquisition criteria that allow you to screen property investments (regardless of the structure) efficiently.There are a lot of folks on here that can help answer questions along the way!

If you can find the right duplex and move into it while you rent out the other apartment, it's a great strategic move. 

Perhaps you could do a duplex with an "overly functional garage" that could be used strategically to recoup the "few hundred dollars each month"!

I echo the above advice to make only the minimum basic repairs: fix the leaks, get rid of the mold, clean it up, stabilize it so water intrusion and whatever issues it has aren't getting worse, maybe do some demo to get rid of major eye-sore areas, slap some paint around strategically, remove trash/overgrown bushes and whatever from the property, improve the curb appeal however possible, apply turd polish liberally... whatever you can do with as little money as possible to make it look a little better, and then wholetail it like a hot potato for whatever you can get. 

The location is very strategic, near the Orlando Convention Center, so it's not the typical vacation rental resort community.

Find your natural strategic advantages and areas you are passionate about and they can help to point you in the direction of the market to get started in and will most likely find the quickest growth in.

Now when talking with the lenders, your "shopping for a strategic financing partner" and curious what they have to offer on this.    

A cost segregation study is a strategic tax planning tool that separates the assets that have a shorter useful life and can be depreciated over 5, 7 and 15 years from the residential rental property or nonresidential real property that are depreciated over 27.5 and 39 years, respectively.

you'd prefer to use HELOCs to leverage temporarily and strategically, not necessarily for non-income-producing long-term holds.