I've been fulltiming for 3 years and have never had a problem. I get 90 day prescriptions and had decided early on to use Walgreens because they are EVERYWHERE. Plan B would be Walmart. I just call my doctor's office and give them the address of the local Walgreens and they electronically send my prescriptions.
I also need a blood test every 90 days so my doctor attaches the lab request to an email and sends to me. I print it and take it to the local Quest or Labcorp, but have also found that I can take it to a hospital.
This was one of the things I was concerned about when I was considering going fulltime but it has turned out to be a non-issue.