If "getting in and out fast" is really that important to you as stated in a different thread, here's a reality check...you posted this question two hours ago. An hour later, you had the answer about right-clicking on the bus to make it the default. Two hours later, and now you have my response that provides additional information relevant to your question that wasn't included in the previous post.
It took me
30 seconds to type
"default output bus for new tracks" Sonar into a search engine box, and the first link not only answered your question and linked to the pertinent page in Sonar's documentation, but that documentation included information on the feature where if you choose
Insert > Multiple Tracks, you can:
- Insert any number of tracks
- Assign them all to the same bus if desired
- Make the bus the default bus for all new tracks
- Include a send in the track if you want, and choose the send destination
- Insert multiple MIDI tracks
- Assign them to a specific port
- Assign them to a specific channel if desired