I don't have a card reader, though I thought my computer would treat my Canon as a storage device (it does that to my fuji finepix camera).
I guess Canon figured "lets make it as easy as possible to use". Sifting through directories doesn't match that very well, so they just "fake" a device where you only see the photos from the various directories. I explicitly mention the last because that is probably why it is read-only as well; in which directory should it put new files?
No, there is no way.
This depends on how hardware was designed - you can not change this.
Well.. after you have CHDK on it, you can use one of the CHDK PTP tools to upload/download any file.
A card reader is VERY inexpensive, it really is essential.
Very much so. At the very least as backup.
I now do wonder how Canon upgrades the firmware. There has to be a way to hijack it to put CHDK on there, right?