But I also sometimes think owning only 1 property in LA would be less stressful and a more reasonable mortgage payment would improve my quality of life.

Then, having covered my base, I'd try to differentiate myself, by having the best located property, the best quality property (given the price of course) and offer the best experience.

Are their listings detailed with good quality photos?

Not sure if Eddie Speed is still around and teaching out of Dallas, but I used to hear him speak years ago and he seemed like he is/was an expert.   

However The barrier to entry in the REI teaching business is very low and a lot of bad players join the game.What you describe led me to come up with Ned's Rule of Gurus.The quality of an REI course is inversely proportional to the price

This attracts a higher-quality renter, ensures funds are available to maintain the home, and reduces the risk of major losses.

A lot of people will pay $1200/nt for 4 crappy budget motel 6 quality rooms at the All-Star resort rather than $175/nt for an 8br themed out mansion with a private pool, theater, and $30,000 arcade room.To answer your original question on investing over a long-term period, that is really this market's main strength. 

For someone that's not as conservative, or a different view on the cycle, they might have a different opinion than me on all of this.2) Sponsor quality check: (takes about 45 minutes per deal)I believe that a great sponsor can take an average looking deal and make it great, and that in mediocre sponsor can take a fantastic looking deal and make it bad (especially if there is a severe recession).

Realtors see Wholesalers as doing a disservice to Seller and Buyer, hence they don't like them.The quality of the Realtor and Wholesaler really matter.

Other factors such as the quality of the tenant, and location will also determine the value you can get.