There's lots of opportunities in developing neighborhoods, but also seems a bit saturated at the moment.Also, definitely budget security (remote control cameras, alarm system, etc.) for your properties, as there are a lot of people who occupy themselves by breaking into houses and stealing anything they can sell.Lastly, there are a ton of contractors looking for a quick buck.

Does this exist in the commercial realm?

Add the financing challenges and that you existing structure likely will become rent controlled.  

I don't think enough people consider this aspect.Selling Stock: Selling part of your portfolio could work, but the 15% capital gains tax might make this an expensive choice unless the stock has underperformed or you’re diversifying away from riskier investments.HELOC: Using a HELOC on an existing property is a flexible and relatively low-cost option.

It is usually difficult to take money against it from the bank, it might not be a 1:1 value add - meaning if you invest 100k into an adu it might not raise your value by 100kThat being said, it can be pretty lucrative especially in expensive and sunny CA - since building lots are no where to be found and existing real estate returns are very poor.My partner builds these units.

They will schedule an inspection to verify that the second bedroom does in fact exist in the apartment.

Don't spend time looking for something that doesn't exist.

Unless you are looking at upper tier properties, you will likely be disappointed in Gatlinburg currently due to the over saturation in that market.

I’ve been offering a $100 referral fee for existing tenants who refer a new tenant to any of my properties.

Well, what would be happening is that your buyer would be buying your house subject to the existing note, since you can't legally sell the property without paying off that note or transferring the debt to the new buyer.