This is one of my favorite "path of progress" areas. For those not in the know... East (not West) Portland, AKA the "warehouse district", is banging. All of the development around 16th and 17th, Bank Street and Lytle Street and the new expansion of waterfront park against the river there is going to make that area golden in a few years. See the already completed "Pilot House" development on 17th for a look at the future of this neighborhood.
Ditto with the east Russell neighborhood, just south of the warehouse district, 16th to 22nd street and north of Broadway. Far too much money and development happening there to not be one of the next great opportunities in Louisville.
And while it's quickly becoming pricey, there are still opportunities to be had in Smoketown. That path was Germantown -> Shelby Park -> Smoketown. Paristown to the east and the new Icehouse development on Logan and what's happening on S. Broadway there will cement that transition. So.Many.New.Builds!
If you just want solid cashflow and ROI without any great thesis about appreciation, look to Shawnee, especially the northwest corner, and Chickasaw.
Just my two cents. Happy hunting!!