Hi Woodduck ,
As of now there is no way to set default city or state in the FIND UI in the
Streets & Trips application . If I search for '3840 148th AVE' in the FIND UI it still finds what I am looking for but it takes a longer time to do so and it will be faster if I just mentioned '3840 148th AVE, Redmond, WA'
To do a search without mentioning the city and state you have to first,
1. Open the FIND UI by clicking the FIND icon from the toolbar or you can press Ctrl+F
2. Then enter the door # and street name in the street address field and then hit <FIND>
But if you don't wish to see the FIND UI and do not want to enter the City and State with the address and always want to default to a particular city and state then you might want to write a custom application using MapPoint 2009
-Gladwin