It is  mostly my time with about 20 tanks of gas a year and other administrative costs. 

@Kamenin Earl Banks Find someone to JV with.....you can do all the administrative things.....and get a partner that does the boots on the ground work.

This is an undue financial and administrative burden.

PENDING LITIGATION: Seller warrants and represents that there are no legal actions, suits or other legal or administrative proceedings, including cases, pending or threatened or similar proceedings affecting the Property or any portion thereof, nor has Seller knowledge that any such action is presently contemplated which might or does affect the conveyance contemplated hereunder.

Should I reach the heirs or the executor/administrator?

I will clarify a legal inaccuracy: if a formal probate has been filed and an executor/administrator appointed, in most jurisdictions it is normal and customary to liquidate estate assets during probate. 

Probate with Letters, Letter of Administration, Trust, etc)2.

The case number your interested in would display as 34-2012-00123080-PR-LA-FRC (LA- Letters of Administration) or 34-2010-00073822-PR-PW-FRC (PW) Probate of Will - Letters Testamentary.

The terms and conditions of this Agreement shall inure to the benefit of and be binding upon any successor trustee under it, as well as upon the executors, administrators, heirs, assigns and all other successors in interest of the Beneficiaries.23.

I use a call center with a carefully crafted script to vet lead calls to determine if the callers meet my very basic criteria (CA real estate, if they are executor, administrator, trustee, etc. and basic property info to determine equity).