What makes this vacant tract more or less valuable than that vacant lot. 

I've been invited to several tract home builds there but developers are too cheap in Santa Ana.

My cost-to-build (very basic conversations with a boutique builder) would land me at the same listing price as developments that were 5 miles away, in a better area, where a "real" (I'm an amateur) developer is building 20 tract homes and getting the associated materials discounts.  

At least that's what small developers tell me, it's probably very different with larger scale tract homes.  

There have been tracts of water front land being bought up recently too, but they have not made a move yet.

- It's also possible that Freddie Mac's Home Possible program could be a solution here, depending on the census tract.- Because FHA 2-4 unit is so much more popular than VA 2-4 unit, FHA appraisers tend to have more experience at rental comps than VA appraisers. 

Some census tracts I do qualify for, others not.

I've recently negotiated a tract of land in East Texas with a mobile home that needs to either be rehabbed or torn down.  

. … As real estate markets receded elsewhere, the District of Columbia blossomed… By some measure, our nation’s capital has become the richest region in the country.”The report goes on to explain how these changes have made Washington D.C. one of fastest-gentrifying cities in the country:“In Washington, according to a study by Governing magazine, 52 percent of Census tracts that were poor in 2000 have since gentrified—more than any other city bar Portland, Oregon.

Are you saying large tracts of land for a subdivision?