Inserting Soft Synths with track settings?

Based on your OP I'd say just create a "Track Template" of your synth track and load it whenever you need into any project you want. Make sure to include any busses you route it to if you have extra effects there but these days, for this purpose, I think you'd be much better off using an Aux Track as your buss and include it in the template (less weird than trying to include an ACTUAL Sonar bus in the template and will do the same thing which can be sent directly to your Master bus or whatever your "entire mix" summing bus/target is).
 
When you save the Template make sure you include everything for that track/set of tracks so it actually saves and loads the desired synth, effects and routing.
 
Hopefully that helps and is what you are asking for.
 
Cheers.

Right. You have to select all the tracks to be included in the template. It will even include folders so if you want create a template from a bunch of tracks (like a multi out drum set up) put all the related tracks into a folder, select the folder (which selects all the track within it... if it doesn't make sure all the tracks are indeed selected) then save as a template.
 
When you insert the template it will all be bundled in the folder. Very nice function.
 
Cheers.