Maybe my hesitation is partly due to feeling lazy about moving, feeling settled in here (cameras, alarm system, patio furniture, etc.) and hesitation about the deal.

Any advice on what are the key rooms in the house to stage or key furniture pieces to have (curtains, etc)?

I don't see any start up costs for furniture in there. 

Colorado is the only state where all water flows out of the state. the water supply is the mountain range.

Demand goes up, supply goes down, prices increase.Cost of buildingAdd to that the cost of materials and cost of labor (due to a lack of construction workers) increased the cost of building.

We are furnishing it with nice-ish furniture (West Elm and CB2.)

Looks like a good deal on some outside furniture for not a lot of dough.

I spent 5k in repairs and supplies for a Short term rental in the ADU.I got my return back and there is no mention of these expense anywhere.

This "can" be a problem if you're buying supplies and things on credit cards to fix the houses.

RE has many aspects (finance, negotiations, sales, marketing, dealing with tenants, accounting, technology, raising money, construction and more); I wish more beginners would take this approach.Tasks might entail anything from going to the property and taking pictures, picking up supplies, doing some admin work, marketing, website building/managing, social media, running initial comps, making follow up calls.