@Mindmatter 

@Former user this is fundamentally the same as the Picture in Picture animation interface, but in the case of PinP just not the mode which people are normally familiar and use (let's suppose, anyway), which would be "Lanes" - and that would be lanes of x, y, and rotation keyframes, respectively.

"CURVES" is the desired mode, which, once selected, its window must then be expanded to look much like the space you, @Former user, are working with above. All the same functionality that I'm seeing here, do correct me if I'm missing something, exists in that space as well.

AS good as that might be, I would probably not use P in P, (though I have done exacty this, i.e., same thing you're demonstrating -- in at least one project a couple of years back. It worked fairly well, even though my technique was raw).

To get the desired effect, I would - as I described previously - use a scroll wheel device, (probably almost any of them would work) and the Pan/Crop window, sync'd to the timeline (engage sync button in P/C) which you can create linear time motion with the scroll wheel (you can pretty much duplicate real time movement), with one hand scrolling, while manipulating the Pan/Crop with the other hand (just as Mindovermatter is doing in his example) and as a result of so doing, keyframes are automatically created and quite a few of them,

The only drawback is that if your computer might be a tad slow - it could have a tendency to glitch every few key frames, not drastically, just a little hitch here and there, and in my case, I attribut that to the computer proving slower than one what would actually do the job sans glitch. YMMV of course. But small glitches don't destroy the effectiveness. One need simple go back and apply a minor correction here and there.

I've done A LOT of compositing with Vegas, and this method, by far, exceeds all others (at least that I'm now aware) as far as ease of execution AND results. Lacking? Well, possibly somethings along the line ot the Vegasaur Key frame routines, collectively called "Tweener" that gives the "ease in" "ease out" "bounce in" "bounce out"... etc.... type of keyframe finesse, which, or it would seem, can be incorporated with the technique I've described after you've gotten your basic movement against time.

I'm using track motion, but works the same as Pan/Crop. I did it because the fish figure was square configuration and I wanted to keep everything 1080/1920 and was taking to long to figure out in Pan/Crop. The key frames are so tight you don't really see them, the just look black. I should have zoomed in, but I'm headed for bed.