I used Bandicam for the screen capture and edit with Sony Movie Studio Platinum 13...which is pretty close to Vegas in many ways. You can get the core Sony Program for under $50 and Bandicam is about $35. They've been great for me. There's a lot of features you can use, in both programs, but you can't edit in Bandicam.
I ONLY use Sonar to record my audio and then sync it with the audio in my camcorder. Therefore in my Sony program I ditch the camcorder audio and use what was recorded in Sonar. You can also use the Cakewalk FX in Sony Movie Studio too.
I've got examples of both types of videos (camcorder and screen capture) on my Youtube channel.... found in my signature.
edit....also in Bandicam, you can record audio thru your computer as well and save the audio as a separate .wav file if you'd like, not mixed in with the video. Typically, I'll do this on my screen capture vids, to give me more control if I might need it.