Since the signs are always on my car, can I write off everything such as all milage and expenses related to the upkeep of the car as a travel expense or am I still required to keep personal millage and business milage on a milage log separately and am only allowed to take the standard millage deduction? 

I would think the license upkeep and MLS dues would wipe out any commissions you'd make.

I own a 5 unit and even for that, they weight the comparable sales approach more than income approach.  

This is what I was reading..For passenger vehicles, trucks, and vans (not meeting the guidelines below), that are used more than 50% in a qualified business use, the total deduction for depreciation including both the Section 179 expense deduction as well as Bonus Depreciation is limited to $11,060 for cars and $11,160 for trucks and vans.Exceptions include the following vehicles: Ambulance or hearse used specifically in your business;Taxis, transport vans, and other vehicles used to specifically transport people or property for hire;Qualified non-personal use vehicles specifically modified for business (i.e. van without seating behind driver, permanent shelving installed, and exterior painted with company’s name).Limits for SUVs or Crossover Vehicles with GVWR above 6,000lbsCertain vehicles (with a gross vehicle weight rating above 6,000 lbs but no more than 14,000 lbs) qualify for expensing up to $25,000 if the vehicle is financed and placed in service prior to December 31 and meet other conditions.

Regarding the other market variables, how does one rationally decide how to weight each variable if one simply has the goal of highest long term IRR for SFH Buy and hold strategy?

People tend to think of a CPA as just an added cost, but a good CPA is worth their weight in gold and makes you much more money than they cost.

I need you to upkeep my social security payments when I retire

It's really that simple, too much weight put into appearance. 

In lots of areas around here, the soil does not have sufficient bearing strength to carry the weight of the house, and it causes houses to shift and sink.  

(Tenants found, maintenance upkeep, etc) I will need to pay a management company, and it will be an expense out of the income to the 401k.