The size of the deal makes a difference.Larger apartment complexes are typically not advertised outside of the Brokerage webist and lists, so unless you're on their list, you may not know those deals exist. 

What locations, property sizes, and target groups work best?

What size/type of contractor crew should I put in place to get things going (for 1-3 fam heavy cosmetic that does not require structural work, $300-500k ARV)? 

It's the small to mid size parks that most people have never heard of but get 500k+ visitors per year that have the best yield.

Medium size 3 bed/2bath that is the most suitable to sell as a single family if the rental doesn't do wall.Any thoughts or advice on the matter would be appreciated!

Many experienced REI wouldn't throw down $5m unless you had a previous relationship with them or track record making money in those sized deals.  

Same size apartments, similar amenities, and similar type of complex if you can find them. 

Would be to sell and perhaps down size.

These are smaller 650 Sq ft 1 bed and studio size apartments.

These areas tend to offer slightly more flexibility, and depending on the size of the property you’re looking for, you might find larger units than in Portland.Also, as Scott mentioned, increasing rents in Portland can be a slow process, especially with the 10% cap or 7% + CPI limits, whichever is lower.