You could also try leaving 1 garage and making less massive master suite but check local code on shard wall with garage. 

I now house hack a duplex and my partner hates having the tenant sharing a wall with us.

Quote from @Jaron Walling: @Jeff Gammon Welcome BP and welcome the journey!

This is because sewer access is sometimes buried behind walls/floors.Questions for buyer agent: Why is the seller selling?

Every now and again another tenant who is a respected doctor complains of marijuana smell coming through the walls.

Renovation PlanScope of Work:Convert 0.5 Bath to Full BathEstimated Cost: $7,500Details: Add shower or bathtub, update fixtures, ensure proper plumbing.Add Bedroom in BasementEstimated Cost: $15,000Details: Install egress window, insulate, add walls, flooring, and electrical work.Replace DeckEstimated Cost: $3,000Details: Replace existing 8'x10' deck with new one.General UpdatesEstimated Cost: $45,000Details: Update kitchen, bathrooms, flooring, paint, fixtures, and necessary repairs.Total Renovation Costs: $70,5004.

@David Walls Thank you!

Fits the relatively narrow spaces well.2) Sliding doors: a little more privacy but more difficult to install.3) Walls: possibly need a permit, but might be easier.

All their units feature at least one whole wall of floor to ceiling windows and I could already dream of the lake and mountain views through them.

As soon as you open up drywall, frame new walls, redo electrical or plumbing your timeline and budget explodes.A good flip follows the same sequence as new construction:1.)