For what its worth, east to west or west to east might depend on the time of year you wish to depart. Earlier in the 'season', then east to west may be a better choice. Leaving in mid June or later? Then perhaps west to east.
I now carry four bottles. One of my earlier rides, when I carried two bottles, resulted in my riding some 25 miles without water because the planned water source had a 'not potable' sign. I was not a happy camper. So I now overcompensate. It also makes it easier if I find myself having to dry camp. I would suggest at least three water bottles.
Also as noted earlier, if you keep your phone off except when you need it then it will last a long time. I personally do not take any extra batteries or power sources. I do not want the weight. I rely on the ac plug in. I use my phone three times a day. I check in with my significant other when I start my daily ride, midway through the day, and at the end of the day. Probably about six to ten minutes per day. It lessens her anxiety level.
Enjoy the adventure.