What are some of the most desirable neighborhoods in Sacramento?

Yes, It is a very popular and desirable location, Location is a Big factor, but it all depends on how you advertise it too!

I will say 4% cap rate is extremely low, even larger more desirable properties are in the 5.5-6.5% range which will change your math significantly

This is a common desire with an uncommon result. 

That, and the upcoming CA ballot measure of possibility of loosing prop 13 property tax freeze status on CA commercial properties, are definitely putting a dent in desirability of owning CA NNN commercial :( 

Where you are going to want to focus your attention is on the leads/skiptracing facets.  1st, unique and proprietary lead sources are hard to come by and expensive. 

Is this a unique tax that's only applicable when using an ira as the down payment?

Most important to me would be their desire and ability to fulfill the terms of our rental agreement.

I actually hope you disagree with me and shed some light on this, but in addition to not having the time/need/desire to get my license, I think it would have hindered many of my conversations with sellers to date.

If it will be a single member LLC verify if that gives you the protection you desire.