Do you have any friends or family that can send them for you?
Before I left I made up all my boxes to the Ashland OR … I labeled them with numbers and the dates they needed to be mailed. I would call my mom a few weeks before I arrived at “X” town to remind her to send the box and had her add anything I needed. All she had to do was seal the prelabeled box and mail it at the post office. My Mom was awesome like that! Then she just kept a list of costs and I paid her back when I got home. This worked well for me, however you need someone you can count on to do this.
Further, when I got to Ashland, I made up my boxes for the rest of the trail. I was afraid post offices would not hold them long enough so I sent my Washington boxes priority to Cascade Locks OR and then bounced my Washington boxes up when I arrived there. It’s free to bounce a box if mailed priority and not opened. This “bounceing” might be a good idea for you if you have no one to help you at home.
This worked for me and I was able to cut up all my Guide books and Yogi pages and distributed them appropriately. I don’t know how picky you are, but, trust me A LOT of towns, especially in Cal have great stores to resupply in.
Happy Hiking!
Floweasy