Is looking online at sites like LoopNet sufficient? 

This is what I did for a cabin I built in Gatlinburg:  We took a few royalty-free photos of the area off of the internet, and submitted them to an art site online whereby they make a painting of the photo.  

Rentmarketplace.com helps with the online application process.

Many PHAs allow you to apply online, but some may require a paper application.

I would go online and check other rentals in your area to see what other management companies are out there, and start contacting them.

By requiring licensing that you think is so onerous, which is usually quite easy to complete and reasonably priced  maybe $1,000 and somewhere between a day and 2 weeks of online classes, we can protect a segment of people that need protection.

I setup one QBO (Quickbooks Online) account to handle multiple LLCs. 

Theres a lot of place online to list like apartments.com, facebook marketplace, realtor.com, trulia, rent.com.

We currently have 105 units and are using a variety of excel, google docs/sheets/calendars, apartments.com (ads and rent collection), docusign and QuickBooks online (which we would like to keep). 

I agree that looking online is only going to get you so far, but I am trying to educate myself as much as possible before taking the next step.I am early on in the process where I am looking at areas that are long distance, as I live in a HCOL area.