Through a little extra research, I discovered that the StorageDevice, part of the GameServices element, is not included without a full premier account. So, I removed the Xbox safe way and now rely on "System.Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)" to get me to a reliably safe location to save files.
I also updated the write routine to make it a little more robust. There are probably some extra steps I can take to ensure that it is not going to crash, but I'll return to that later.
I might need to just go over some notes tomorrow and try to decide what should be my next focus. I'm also toying with the idea of some NUnit tests.
Or, I might research collision a bit more, since there is only the appearance of movement right now; projectiles disappear from one position and then reappear a predefined distance further along, making it possible for very fast projectiles to skip over the growths altogether. Yes, I think this will be tomorrow's focus.