Maybe this is in the owner's expenses already, but if not, that leaves $62/mo for everything else, while still maintaining $540 of free cash flow.One of the biggest items that should be easy to figure out is real estate taxes.  

Some state's charge onerous fees to maintain an LLC while others are dirt cheap.

Doesn't the cost of holding a note, change the yield that's projected? (i.e. monthly servicing costs etc.)  And, if so, how do you remedy that?
Thanks for any advise.

So, yes, to scale you either have to hire a property management company or become a property management company.You have to study your own finances, the equity available, your tax strategy, the availability of opportunities for what you could do with freed up money to answer your last question.

I maintain the roof and the black water drain. 

As for the tax side of the question, your CPA can guide you on the tax benefits and risks before you start the Series LLC, but they should be very involved in your record keeping during the year to make sure you maintain separate records of the Series LLC while they are in operation (read the Texas Series LLC statute regarding record keeping required to maintain separate Series status).

Currently, the property has been rezoned for multifamily but there was no actual feasibility study done on the actual structure on the property, it was based on civil engineering print, population density, and square footage to approve the number of units. 

I am just beginning my real estate investment journey and have been doing quite a bit of reading and studying over the last few months. 

We did want acreage, although it's not our ideal locationAdvantages - enjoy the acreage, lock in the gains on our current home, let our income grow over the next few years and purchase a "dream" property in a more desirable location.I also believe this would increase our gains significantlyDisadvantages - maintaining acreage, cost of moving and getting a new home built or M/H setup, and having to move in a few more years.

My wife and I live in Florida, she will soon be moving to Richmond Virginia to study.