The more I have learned the more the more exciting it has become to get involved.I have narrowed my search to apartment investments in Phoenix, Salt Lake City, Bakersfield CA and Las Vegas. 

Hi @Alex B and welcome to BP.

 Avoid zip code 53205 for nowMy suggestion would be to start visiting local areas and narrow down your preference.Visit:  Grocery stores , gas stations, Home depot, Lowes, and etcDrive by and start studying the community.

But, in life we should make decisions that give us the greatest percentage chance of success.If you have a very handy partner then that relationship is an advantage that you might want to leverage, by fixing and flipping or self managing some buy and holds.I think the property itself will limit the options you have to chose between and some self analysis will further narrow your options and you will land on what is an ideal choice, for you.   

I am trying to narrow down markets with research here, now.

Have you narrowed down what types of investment properties you're looking for?

Cudos to you for narrowing down your search list, there is a lot of information to sort through out there, but bottom line, a lot of the work starts after the offer is made and the property goes under contract. 

We've been able to narrow down that we want to start with multi-family, somewhere between 5 - 14 units.

Direct mail is a great way to get your name and contact information out there and readily available for future reference and use.As for narrowing down the amount of leads to mail to, I agree with Tom T., target one or two zip codes at a time.

Like you said all properties are different, but if I had to narrow down an agent's time required to just list a property I would say right around 6-8 hours.