The buzzer system has gone bad and I have been quoted 2.5-3k+ to essentially put in a new, but still same technology system that has been used for the last 20+ years.I've been reading a lot about wi-fi connected smart deadbolts that you can open with a phone.

The Bigger Pockets Blog https://www.biggerpockets.com/renewsblog/is a great resource for all aspects of real estate investing.

There is no difference in time to manage respective portfolios, both require constant attention and deep knowledge.As to liquidity, most investors only need a fraction of their investment portfolio for liquidity so this risk can be managed (and should be) in a balanced and disciplined manner.Leverage aspects of real estate are far superior to equity/debt portfolios. 

.) - this can tell you a great deal about reliability of the income for a number of reasons.2) Does the Seller own the tower (or is it a rooftop install) - if it is actually a tower and the Seller does not own it, upside from an additional carrier may not exist (all depends on the lease).There are a great deal of additional aspects to consider, but most of them require more information.

My background is mostly technology based having worked in Cell phone Sales, Computer repair, and running a small eBay reselling business.

I just posted this question, because the Real estate Gurus do not mention the "What If things go wrong" aspect of this business.

They also offer a ton of electives, I went with Legal Aspects of RE. 

Quick background on me, I currently live in Jersey City with my wife and daughter and work in advertising technology in NYC.

This is a crucial step IMO that I see a lot of newbies make and try to skip to step 4 to apply advise they get online from a completely different market to apply to their own, when it may or may not be applicable or wise.Based on what the locals say is working, if any of those aspects appeal to you then formulate your own strategy accordingly.

Learn every aspect of the job, it will make you more valuable.