If your floor is not level, you may need to prep it with a self leveler product, which can be expensive.  

Some of this will cover expenses, but the extra will increase their cash flow.

@Malcom FlenouryDepends on what you're planning to do from REI standpoint.

Hawaii is #1 most expensive state in US so it's more suitable for appreciation/flips play.

I imagine a situation where you rent an expensive piece of machinery, and then their employee damages it, and now your left trying to collect from their insurance while being on the hook with the rental company.  

What is your plan? 

I have some thoughts to your question:1) Maintenance service plans (requires agreement with preferred vendor, or if you have maintenance staff, through your company)2) Landlord liability insurance through third-party insurance providers (note: this is in addition to a Dwelling Policy, which the owner should already have)3) Lawn maintenance service programs (requires agreement with a vendor for agreed-upon pricing, or if you have lawn staff to provide this service, through your company)4) Fee in lieu of security deposit (requires agreement with insurance company that provides this service)5) Increased inspection options (e.g.

I'd like to find a way to cover all the expenses I still had to come up with myself 

OK, your expenses are $1400 a month and you're netting $100 a month, or $1200 a year.  

California is an expensive market.