We stayed for three nights in early August. The place was appropriate for the 9 people in our group. The house was recently remodeled and well-kempt in a quiet neighborhood. A grocery store was five minutes away. There was a spacious pool deck and the pool was large and pleasant. The kitchen was well-supplied. The beds were comfortable. There were tables on the patio, so coffee in the morning, while it was still cool outside was nice, as was supper by the barbecue. The host family was helpful.
In Walla Walla, we visited several wineries, both downtown and in the surrounding area. Downtown we visited a great antique store and one of the most impressive used CD/vinyl stores I have been in. When visiting the wineries, the tastings are $20 per person, but the tasting charge is waived when you buy wine. Therefore, use the opportunity for tasting informally, perhaps with a cheeseboard. Then buy a bottle of wine for each tasting done. In effect, you end up with a tasting and half-price wine. Not a bad deal. Given the heat in Walla Walla, you'll also need lots of water.
All-in-all, a very pleasant re-introduction to Walla Walla made special by our hosts sharing a nice home with my family.