Hi Shane, Welcome to the Forum!
This is the same problem that lots of people encounter. I want just a couple of "F" or "G" motors, and Hobbytown USA doesn't carry anything bigger than an Estes "D" or "E". You can order online, but that Hazmat fee takes a big bite out of the rocketry budget.
This is where a Rocketry Club comes into play. You may need to drive - and it might not be real close. Some folks drive 2 or 3 hours to get to a Rocket Club launch.
At a club launch you will find a lot of friendly people launching all kinds of rockets, many with "larger" motors. It's a great opportunity to make new friends, ask questions, get ideas, take pictures, etc.
- AND -
Most big launches have an On-Site VENDOR - selling rocket motors and other rocketry stuff. Bring some money and a camera, leave with lots of new ideas and those "F" motors you've been wanting to try.
I'm sure you get some additional answers from members of the Washington Aerospace Rocketry Club
https://www.washingtonaerospace.org/
SunRiver Nature Center and
Bay Area Rocketry are two of the vendors I can think of - that you might see at a local launch.