If I'm wrong, my apologies.Suggest you spend some time, money and effort on your real estate education before tackling probate (or multi-family residential or high-rise commercial, for that matter). 

I am a new investor but very active in wholesaling right now;  I'm looking to tackle other avenues in real estate.

Large deals like apartments may also invite non-recourse debt, but there are a lot of other hoops to learn to jump through before tackling 100 units, so I recommend start small.  

I would have to make sure I knew of a GC or rehab experts in case I wanted to tackle a big fixer deal (know rehab costs and schedule to pass on to the buyer or for me if I buy).

I'm far from a professional yet, and our properties are nothing to brag about, but I could probably save you some headache if you decide to tackle some plumbing and run into trouble. 

It would be nice to talk to someone tackling the same obstacles to get an insight. 

Some big takeaways  for investors at any level are, overcoming fear,  thinking outside the box, 10x effort, and tackling challenges as they come.  

I'm building my own CRM and SMS management is the first issue I'm tackling.