I stayed in the Little Green House for just over a week. The place is really easy to get to from the airport and downtown Portland on public transport via the frequent #4 bus, that stops right near by, and the MAX yellow line, which is a 10 min walk away using a bridge to cross the highway (although perhaps I wouldn't want to walk there in the evening).
Check-in was easy, I didn't meet Rick but his communications were clear and concise. I did meet Kristin, and she was welcoming and friendly. I had an issue with the keypad not working, however it was rectified the next day.
The space is small, but charming and perfectly formed: the Murphy bed was very comfortable, the bathroom was clean, and the kitchenette served for a quick breakfast. Other reviews spoke of a loft space, but unfortunately this is unavailable so be prepared to have to shuffle suitcases around as you convert the floor space from living room to bedroom, I didn't find this a chore as it became part of the nighttime routine. It was cool this February but the heat worked without issues.
Mississippi Ave is an eclectic mix of breweries, bars, cafes (Blue Star donuts, yum), eateries and shops like Pistils Nursery that specializes in succulents and terrariums.
I really liked the feel of the home and the neighborhood - I would definitely recommend it for solo travellers or couples.