I'd rather spend the money used to form and administer more LLCs on an umbrella policy that will cover all of my rentals.

I work for a company that administers self-directed IRAs and it is possible to invest in stocks.

What you are referring is a Solo-401k or Solo-IRA.There are a number of companies that can set up and administer your account.

All operations of the rental cabin will be administered through the LLC.  

Accountants, Insurance agents, financial planners, stock brokers, tax people, Trust administrators, loan officers at banks (banks won't buy a seller financed note) bankruptcy attorneys, any government office that administers public benefit programs: Division of family services, welfare office, medicare, don't think that a note holder is always wealthy, they inherit a note and can't live off a $300 payment, the note is an asset and disqualifies  people from receiving benefits.When I said "they called me" it wasn't just note holders, many times it was the people trying to work with the note holder, they had a problem to solve to assist their client.I was the only Note Appraiser in the state, I believe, the state sent me notes to appraise!

Do I have to mail to the executor/ administer? 

Check in with the office that administers the Section 8 program (usually the local Housing Authority) and find out if there's anything different you need to do because the tenant has a Section 8 Housing Choice Voucher. 

We administer these Reverse 1031 Exchange transactions all the time.

Talk is cheap.Section 8 has some homeowner ship type programs already.They would need to talk to her case worker first about this to see what options there are.Each area calls section 8 something different sometimes as it is administered locally.

The plan can be self-administered which could mean significant savings $$ on custodian, transactions and asset based fees that would be there in a case of SD IRA.