For the purpose of adopting a Solo 401k Plan, the IRS and tax code care about "trade or business" activity.What is a "trade or business?" 

.  :-)My Baltimore City permits average about $50 per trade...

Smaller local markets are harder to nail down accurate ARVs and find reliable trade labor.Regarding managing general contractors, I've heard some horror stories from our owners who have worked with GCs they've never met.

Repeat the above procedure and get a Roofing cert, chimney cert, HVAC, plumbing, electrical cert or statement of recent service and opionion of condition, etc for any other prefessional trade that might be an issue.

One of the misconceptions investors have is they open a LLC for real estate and owning rentals and think they can get business credit, which would be like opening a LLC to trade stocks - business must be operating and generate revenue and EBITDA

The other side of it is that paying 5 or 7% for a heloc to invest in something that is making you 8 - 10% is a pretty good trade - especially if the other option is taking a 20% hit and then investing the rest. 

You can get some education, network with other investors, trades, lenders etc., that may be looking to partner with someone with your skill set or time availability. 

Ford Motor Credit will do no pg business auto loans/leases, but you need a strong DNB profile, with high trade limits reporting.

They may hire a contractor (they use the same guy and he's done a great job so far) or a specialized trade for anything more advanced - electrical, plumbing etc. 

Just depends on how much you want to cash flow, your down payment, loan type... and what areas you're open to (in terms of neighborhood ratings - C/D areas cash flow well but the trade off is a higher chance that rehab is needed between tenants).