After leaving the service he was employed with Proctor and Gamble in sales.

The gamble will be: how long will the Tenant last, and/or how much will the land appreciate?

Properties at this price point and in this kind of neighborhood are hard to insure and costly, so it was a gamble on your part, to not insure them.  

How ever when I asked her this question twice, she told me that it will only work on PC.Not sure if I want to spend around $100 for this gamble.

It's always a gamble.

My wife (who is Chinese background) knows from real estate agents that have done very well for themselves and some friends chasing the hot developments - residential SFR/presales and commercial, for offshore Chinese investors.

They then go from 5 million to 1.5 and run with their tail between their legs for awhile to lick their wounds before they jump on the next cycle again.Another mistake is to tell yourself you have some good properties throwing off cash and then it makes sense to gamble on a marginal deal that might work out.

The worst thing to do is (well, other than gamble it all away or use it on drugs/booze) is to rush into something unprepared.There are lots of ways to invest it:- Stocks, bonds, mutual funds- CDs, high-yield savings accounts (which really aren't that high yield)- REITs- Private lending for flips- Private lending for buy and holds- Do your own buy and holds with a property manager- Partner for flips or buy and hold where you have an equity stakeEtc.

They know that the stock market is considered to be a "gamble" and a rise/fall does not affect their overseas real estate decision making. 

@Manolo D. is right that you are taking a big gamble.