Hello and welcome to the Seattle forum!
I live in Duvall and can tell you it is a very nice area.
We quite a mixture of people living here, a lot of Microsoft employees and as such there are quite a few younger families with children in the area. We used to be a farming community, so there were quite a few farmers at one time...still a few around, but not many.
The downtown area of Duvall has undergone quite a transformation in recent years. At one time there was just one grocery store and one gas station. Now, we have a Safeway and the trusty old Family Grocer and three gas stations.
We also have a fairly decent selection of restaurants for a town our size, nothing fancy, but decent. There are several antique shops downtown, a hardware store, Starbucks, etc.
Duvall is divided up between upper Duvall and lower Duvall. Lower Duvall is older, tends to have older, smaller homes and it seems to have an older population. Upper Duvall is newer, has quite a few housing developments and has a younger population.
The commute to downtown Seattle is approximately thirty miles one way and at peak commute times can take well over an hour. I wouldn't want to commute to downtown Seattle, but many people do.
Overall, Duvall is a very pleasant community.
Redmond Ridge, which is just a couple of miles west of Duvall has a newer, master planned community called Trilogy, here is a link to their website.
Trilogy
Trilogy