By the time we got to that level, it was getting a little busier (and we had enough income to start quitting our corporate day jobs, but still nothing we couldn't handle (recognizing the amount of gain we were getting from it).  

What you need are short-term financing options to handle repairs when they go boom-boom in your life.Of course, the best solution is to have a war chest ready to go, built through careful capital expenditure budgeting and saving.

As mentioned above however I'd suggest a legal team on your side to provide the proper notices and handle everything accordingly. 

I'm looking for a general rule-of-thumb for estimating the percentage of gross income used for paying for a management company to handle an STR. 

I've seen the amount for repairs that the tenant is responsible for handling increase over the years I'm sure for just this reason. 

Id include that the penalty for improper handling of the security deposit is 2x the deposit.

It sounds like you have a pretty good handle on some next steps to propel yourself forward.

Hi Ting,I've had Pest Control companies that layed down a DMZ of sorts outside the buildings.Fire ants, ants, and a lot of other crawlies seem to stay away from the DMZ area--keeping them out of the house.I've had them do it in the pouring rain and on nice days.Maybe they do something like that in your area.If it's a problem, you can scheduled ongoing service for it--where they will come out and re-apply.Or you could pass the info on to the renter--it's less costly then her hiring an attorney (unless she is govt subsidized and gets free attorneys via legal aid).They also do a building inspection inside and out--looking for entry points that need to be "Repaired", but ants get in through the smallest cracks.If you have a slab foundation, they may be under the slab and coming through a crack in it--exterminators can handle that.One or two phone calls will get you a quick price, and being there when it happens to take notes on where the tech says to repair to prevent other insects coming in might be a smart move.I've seen long lines of ants outdoors coming up a metal handrail to an apartment and going into a tiny space at the corner of a window and into the apartment. 

A few barks here and there most people can handle but a dog that owners let bark all day and all night is a whole other story.  

Obviously she has been paying the previous owner every month--but it's up to you how you want to handle it.Have you ever been to Detroit (???)