From my research, the 2 main variables (removing the tank in basement and adding chain link fence in backyard) can both easily be done within a few days of taking possession. 

"MARIJUANA AND OTHER DRUGS: Tenant shall not be permitted to, and shall not permit any family, visiting friends, dependents, guests, licensees or invitees of Tenant to grow, produce, possess, consume, use, smoke, or ingest any marijuana, cannibas or any products or ingestibles containing marijuana or cannibas in any location in, on or about the Premises; the foregoing prohibition to be absolute and without exception and shall include any growing, production, possession, use or consumption pursuant to any medical use or medical prescription, or any medical, retail or recreational marijuana activities that may otherwise be permitted under any local, state or federal laws, rules or regulations now or hereafter in effect.

When we took possession, it was a quick clean out and demo.

Hello, our tenant unfortunately passed away and we’re trying to understand the legalities of taking possession of our rental property.

You may not get possession of this property in the year 2020. 

Since the OMI is temporarily off the table, you have no sure way of moving into a tenant-occupied property as an owner once you take possession.

If house not vacated, you file for writ of possession and wait another 3 to 4 weeks.

That's without saying too, most new landlords are scared to death and try so hard to cover any possible issue that they end up restricting quiet enjoyment and rights of possession which you're supposed to be granting.  

If the crooks ever find out you have a large amount of cash in your possession, you might get held up.

You are the beneficiary of the trust.You and your personal possessions are well armored.