Hopefully someone can help shed some light on what my options here are:I've been speaking to my dad, who is a service disabled retired veteran, about working together on some REI deals.

Ask the title companies.But take heart if the goal is good service with an experienced accommodator. 

Call Luke at 970 Services!

However, the solo 401k plan permits an in-service distribution of such amounts upon attainment of age 59 ½ or upon a Hardship.https://www.irs.gov/retirement-plans/plan-particip...

Places that are growing, Also, I'd do a quick few hours of digging on even zillow, and get some data points of highest ratio of average rent price/average sales price of SFH.This will get you pointed in the right direction to get independently informed...

An engineer's mind may need higher control over investment :))) let's check on the scenario of independent investing: with 40K down and conventional mortgage you could get a decent quality old duplex in the good location of Midwest. 

IMO, that's the simplest way to get started for service members.

It will likely depend more on the property's debt service coverage ratio than on an arbitrary percentage. 

My Contractor an I visited both properties and he provided the quote for services and materials.

Also, it creates value as properties are improved and a service is offered.