A change in the mix of buyers to more investors and concentrated ownership from those with money and income?

If you have got enough concentrated cash over the years, work and build use of it to serve the underlying purpose.

For now I am going to concentrate on fixing up all the high dollar items on my houses to weather the storm, and to pay down one or two of my lowest mortgages to reduce cash outlays in case I start getting vacancies. 

My hesitation with the higher priced & larger homes in Charlotte is you're concentrating your risk into one property.

if so I would be less concerned about the long term viability of gas.It might be a case where gas stations are a great investment but not really a good investment for your dad based on his age, concentration of risk with his investment portfolio and the number of current leases coming due in the next 5 years.Personally I think we will see a move to electric, but I also think we are on the verge of self driving vehicles. 

@Cody Nielsen  To answer your question about areas of Tahoe I like, the restrictions on STR's in the South Tahoe area (google Measure T Lake Tahoe) and just my personal preference kept me concentrated in the West & North shore areas. 

Those are the areas I am concentrating on.

At the time I asked, Dave had said they are invested across the country with no special concentration in any particular region.  

Clumping clay based kitty litter contains lead dust and can concentrate on floor in excess of federal lead safe standards.   

But let's not forget that a points leader does not necessarily mean an influence leader.There are people like me out here that read and learn and reply to many (sometimes incorrectly) who have good numbers but my influence is only in a small niche area that I concentrate in.Do not take someone's word as gospel just because of their numbers.