I've heard of some drive-by appraisals and some desk appraisals (basically just comping the property from what's viewed on the internet), but it seems case by case.

In my area (San Diego) there is a company (Maxable: no affiliation - I do not know if they support WA state but think it unlikely) that has a reasonable ADU consultation fee. 

While e-commerce has been growing quickly and increasing its share of retail spending, Americans finished the decade making 84% of their purchases in retail store locations with the total dollars spent in-store increasing by over 26%, from $2.4 Trillion to $3.2 Trillion, over the past 10 years.As retail has changed, the distinction between a purchase made through the internet and a physical location has been blurred.

You won't get this experience quickly on the Internet nor by limiting yourself to a subset of buyers. 

Keep it simple, and don't take any shortcuts; buy in or near Pittsburg, or some place else where you have familiarity and connections, set yourself up with a local RE agent and interview some PM's, you can do a lot over the internet from anywhere, but focus on seeing properties during your periods in the US.

Pet ParkEV Car Charging StationModernized Hallways & SignageInterior Remodel: Kitchen with Mosaic Backsplash, Stainless Steel AppliancesLVT Flooring ThroughoutNew Modernized Bathroom with Tile Surround and New Water Sense FixturesNEW LED Lighting, USB Outlet, New Outlets, New SwitchesTech Package: Smartland Wi-Fi Internet*, Nest Thermostat, Alexa, Digital Door Locks (No More Keys)8th Floor Community Room with 270 Degree Lake View (New Windows, Activities, Comfortable Zen Seating, Full Service Kitchen & Bathroom)Much More........

Pet ParkEV Car Charging StationModernized Hallways & SignageInterior Remodel: Kitchen with Mosaic Backsplash, Stainless Steel AppliancesLVT Flooring ThroughoutNew Modernized Bathroom with Tile Surround and New Water Sense FixturesNEW LED Lighting, USB OutletTech Package: Smartland Wi-Fi Internet*, Nest Thermostat, Alexa, Digital Door Locks What made you interested in investing in this type of deal?

I listened to every BP podcast, became somewhat active on the forums, read dozens of books, too many internet searches to name, and analyzed deals on the MLS and through wholesalers. 

The previous owners had a horrid prop. management company, a Real Property Management affiliate, and there was basically no work done to maintain the home. 

I've been looking around on the internet and I can't figure it out.