I grew up in the Phoenix area and rode in lots of sand. I would agree with all of the above except for 7. Once you're in the sand and fall over it's not so bad. You can, however, get really hurt entering the sand if you bury the front wheel causing horrible endos.
Some things I've learned when riding in sand:
1. Steer with your hips more than your arms.
2. Keep your weight back so as not to bury the front wheel.
3. Pick a gear or two lower and keep a fast cadence (90-100, at least).
4. Stay loose, it's usually better to let the bike wander a little than to force it to a narrow path.