Ok, I answered most of my questions I think. I found these excellent videos that describe the whole process and more!
long video:
Viewing Your Model in Google Earth
shorter video:
Exporting Your SketchUp Model to Google Earth - The SketchUp Essentials #28
So I proceeded to get Sketchup. Unfortunately, the only version that is affordable to me is the free Web version. I just want to visualize some local development around me, as one-time only project, so it doesn't make sense use anything but free.
Unfortunately the free web version seems broken:
1. I was able to "add location" and grabbed a section of a map just like the video shows. Unfortunately, it's only Open Maps, with no satellite. I guess Sketchup doesn't pay Google to licence their imagery? So that's not very helpful and it means I won't be able to use the Google imagery to make realistic-looking models.
2. I found 3 existing models in the 3D warehouse, and tried importing them. After a long delay (my connection is only 7 Mbps down, 1 up), my grabbed map disappeared and the imported 3D model is nowhere to be seen - just the axes. When I started fresh and skipped the map grab, and imported the model, it displayed just fine. Not sure why I can't have both. I thought everything was there, but just to small to see, so I zoomed in (seemingly forever) and never saw anything other than the axes.
3. the video shows how to uses the "axes" tool to re-align the axes parallel to roads (for example). But I don't see any such "axes" tool on the free Web version.
If I'm doing something wrong, please advise. Is that my only choice for Free or cheap software to visualize these proposed buildings?
Thanks.