I've been thinking about breaking the project into bite-sized pieces rather than the chaos and large monetary bet of an all-at-once, fast-as-possible, project. Putting wild guesses on the stages, it looks like about $114,000 which is the right ballpark. (Please, correct me if a guess seems wrong.)
1. Clear out the overgrown landscaping, remove the back deck, reclaim the gazebo and water feature. Electrical for monument street light, lighting at gazebo. New paving/steps in places. The house could be put on the market if I wanted after just this stage. $3?
2. Remodel BR3. Re-do bathroom, revise wall at garage (remove closet, door to garage). Install new garden door, new window in bathroom (close existing window). Plumber--confirm sump pump, rough in new breezeway drains, supply. Fresh paint. At this point, we could rent or AirBNB the room. $20?
3. Remodel the kitchen/laundry. Remove greenhouse window, new refrigerator/appliances and cabinets. Rough-in for laundry in the hall (electrical, plumbing). Fresh paint on exterior at kitchen at least. $8 + appliances $6 = $14?
4. Further work on main house - refinish hardwood floors, improve MBa (replace door with window). Move laundry. Improve guest bath. Replace mirror in living room. Fix chimney (install damper, repoint mortar). Install garden door on east wall of living room? Repair drywall at ceiling, repaint. At this point, I could buy real furniture. $5?
5. Expand breezeway (130 SF). Build new foundation. Remove laundry closet and wall at BR3. Frame roof/ceiling. Revise stairs to BR3. Rough in new laundry/kitchen. Build deck. New entry door, windows. Revise electrical for breezeway. Build partition to separate main house. Tenant would find this disruptive. $25?
6. Expand garage (160 SF). Build new foundation. Extend hip roof. New roll-up doors. Pave driveway (without damaging Douglas Fir roots--tbd). Workshop electrical. Drywall interior, make attic storage more accessible. New roof over entire house, new gutters. New paint on North side at least. Tenant would find this disruptive, but once it's done I could get a real renter going forward. $25 + roof $22 = $47?
If I invest $114, my sunk cost is about $592.
Zillow thinks I can get $808. If so, subtracting $50 for commissions and excise tax, I'd make $166 profit; 28% return. Reality is probably less, but it makes investing the $114 seem sensible.