The Vasst Ultimate S Pro 4.x Quadcam plug-in will allow you to work as you suggested. I use it in exactly the way you describe. I work on the events at track level and apply FX and do what ever pan and crop is needed.
I believe the built-in multi-cam plugin that ships with Vegas is a bit limited, and I have not used it more than once, after which I got too frustrated with its limitations.
The Quadcam within Ultimate S is a bit quirky at first to use (perhaps because I did not fully RTFM), especially after you have processed the cameras to create the Master track and notice the lower tracks bleed through with the MC-Tally and MC-Overlay. I simply mute the lower video tracks once I have created the Master. Titles need to be on the top most track.
Download a free trial of Ultimate S. Some of this will make sense once you use the plugin. If you do lots of multi-cam work, this plugin is a must. If you need to use more than 4 cameras, you should look into Infiniticam. Once again, the user interface has a few quirks, but you should be able to figure them out.
I have used both and would highly recommend you check out Ultimate S Pro 4.x. I use Ultimate S almost in every project I do.
My system specs: Intel i7 970, 12GB RAM, ASUS P6T, Vegas Pro 10e (x32/x64), Windows 7 x64 Ultimate, Vegas Production Assistant 1.0, VASST Ultimate S Pro 4.1, Neat Video Pro 2.6