I don't think Sonar lets you treat a track output as a real-time input for another track, no. Track outputs and sends can be real-time inputs for buses, but they don't record, meaning that's fine for listening but not for recording. (If that's not good enough, REAPER is a cheap DAW and will let you route one track to another track, and switch the recording input on the receiving track to 'Monitor Input', so you can record it that way if you choose.)
However: if you just want a fixed audio copy of what your synth sounds like, you can use the Freeze or Bounce options in Sonar. That should work for your EZDrummer problem.
If, however, by "set my record offset" you mean "measure how long it takes to send output from Sonar and receive it again", then what you need to do depends on exactly what you want to time. If you're trying to work out your sound card's latency (eg. to do manual compensation) then routing within Sonar is a waste of time - it cuts out the sound card completely. To measure that, you'll need to use the loopback cable method. And if you're trying to time the 'internal' routing speed, then that is almost always zero because Sonar automatically compensates for synth and FX delays. But if you're worried that a synth is misbehaving, you can use the freeze method I mentioned above - ensure your MIDI note or initial audio sound is right on the grid, freeze or bounce the track, then check that the output audio is also still on the grid - if it's not, you've found some delay.