Another alternative that gives you quicker access to cash would be to borrow against it now.  

You could get them on MLS (I don't believe real investor will buy it from you, because they probably have REA they work with, access to Zillow, Redfin and etc., just doesn't make sense to pay you extra fee to get what is already blasted there for ALL to see).

Be careful if the actual contract has any terms about assignment or allows their private access to the home before closing, as many "cash" buyers out there try to tie up your house for a low figure, then sell it higher to someone else before they decide to close it with you. 

The outstanding balance after 5 years (60 payments) will be approximately $364,814.The buyer would need to pay this amount at the end of the 5-year term, typically through refinancing or other financial arrangements.Using the Promissory Note for Financing in Florida:The promissory note valued at $400,000 from the sale can be used as collateral.Assuming you can get a loan of 75% of the note's value, you could potentially access $300,000 to assist in purchasing your new home in Florida.This detailed scenario underscores the potential benefits of seller financing, such as generating additional cash flow and converting equity into liquid capital for reinvestment.

Will it have access without disturbing who lives in the main house?

We also are considering closing off the brown door in the picture (access to the attic) and creating access elsewhere. 

Refinancing to access your equity, using 1031 exchanges to upgrade your portfolio, and leveraging HELOCs for flexibility will help you expand and improve your cash flow.

Those same restrictions can have positive long term investment trends by creating a higher barrier to entry for new investors, and theoretically greater return or demand for those that are operating.

Unless it's a very restrictive area, typically this type of housing is allowed with 30-day minimums. 

While it provides significant benefits to lenders, it also imposes restrictions and potential challenges for borrowers.