Turnkey providers should have a system in place to allow for modest revenue generation and developing relationships with contractors/vendors to provide those services at their cost with a small administrative fee.

It will also limit your access to financing and may increase some other administrative chores.Using LLC is an excellent tool for asset protection.

Anyway, several administrative things you can do (no particular order):Send appraiser before pics Provide rehab list of work doneRun your own comps and let the appraiser know where you think the value should beBe present for appraisal and show work doneGet house professionally cleaned (someone who does this for a living, not tenants). 

Anyone know where to get a good list or start creating a database?

The  benefits of the SOLO401K are the much higher contribution limits, and the fact that you can be your own 'administrator' (not sure if that is the correct term) and that IF you want to borrow non-recourse money there is next to no paperwork, or tax, involved compared to the SDIRA. 

Your database should consist of individuals, friends and family members that already "know you, like you, and trust you".

Even sophisticated folks rely, at best, on databases like CoStar and REIS which hardly provide any big data analytics.

Compared to an IRA, Solo 401k contributions limits are roughly ten times higher.There is no custodial requirement for the 401k.You don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.The Solo 401k has additional tax benefits over an IRA when investing into real estate using leverage.The penalties for prohibited transactions are less severe.

HUD pushes the administration of the vouchers down to the city level, so people are stuck in the one city unless they port.  

@Darius TracyPlan Administrator of the TSP has list of investment options available for that plan, and it is always confined to the stock market, they would not allow alternative investment options such as real estate.