If possible, go to a local crypto meetup and ask around there for a referral.  

The building is in excellent shape so mostly I go there every 2 weeks to check in and collect coin op laundry money.

The industry has coined the term "swap 'til you drop" to help explain it.  

Coin Laundry, Snow Removal (if your streets are not dedicated back to the county), Lawn Mowing (technically each is responsible for their own lot, but you end up with several heights of grass and random lawnmowers strewn about)

That's some nice coin.  

Returns will vary with the level of risk - for example if there was a "crypto currency fund" that targeted 15% or a US Treasury Fund targeting 4%, most would be like of course 15%, but risk is also a major key component. 

It’s estimated that the American investing public lost in excess of $600 Billion investing in Initial Coin Offerings, of which it was found that 84% were outright scams, and 92% were structured so that it was impossible for the purchasers of these “coins” to make any money.

Another option is to have a laundry room with coin machines.

Almost as bad as crypto, except transactional costs being higher for gold.

These units sit atop 4 one car garages, 3 of them with 75 sq ft storage areas behind, the 4th garage has a coin-op laundry room where the storage area would be, accessible from the outside.Minimal work needed to be done; new faucets, light fixtures, carpet cleaning, cleaning garages, door handles, and garage locks.