It may have given me additional confidence confirming I was reading the market correctly, but in hind-sight it's no substitute for local market knowledge.

Its not a substitute for your life.

Include a substitution of collateral clause so you have the option to move the debt to another property, a subordination clause to secure 1st position financing, and reserve a pre-payment discount.Charles Parrish

Possibly tracking substitution of trustee filings for when the lender transfers over to a default trustee?

Sure, it can be if it's a small investment, but if it's big enough to substitute a regular job, it comes with work. :) In the last 18 years, the only truly hands-off investing we've done is pre-con assignments.

., and Anaheim (where I currently work as a public school substitute teacher).

Niether is a substitute for the other as they are different things.4.  

(A recorded                  trustee's deed [or similar alternative] confirming the amount paid by the grantee                  to trustee may be substituted for a HUD-1 if a HUD-1 was not provided to the purchaser                  at time of sale.)                 

The short answer is that it is nearly impossible to remove/limit a previously executed guaranty unless you provide with the bank with comparable substitute collateral, i.e. the new guy executes a guaranty as well, the company pledges additional assets, etc.

Land can not be substituted, all other factors may be, more of one can mean less of another is necessary.