Will, I've attempted extensively to work with the Civil Air Patrol (CAP) when it comes to model rocketry. Extensively, both here in Mo and in Ak; from the active duty side as well as a pilot/educator side.
The first and foremost issue is like with many - monetary. To the best of my knowledge they still remain an auxillary of the USAF, where the bulk of their money comes from. They do take donations. Even if a CAP team was to become active towards TARC, you face two uphill battles; micromanagement from adult leaders (it's a military thing) and the second is having to accomodate even more activities into a compacted schedule to earn the resources for the trip to VA.
Many CAP squadrons are still organized around Search and Rescue (SAR), even though they're fully permitted to pursue model rocketry and can form such a squadron. I've worked these folks over, over, over, and over again attempting a "low cost" alternative to SAR geared activities. There's simply no glamour in it.
In AK the CAP was so heavily focused on their SAR mission, for obvious reasons, that they had a waiting list of people clamoring to be pilot/observers.
In MO I'm surrounded by 3 squadrons within a 100 mile radius, at last call, I've contacted all three squadron commanders extensively, explaining that I myself am a USAF guy and get a friendly conversation and no call backs.
From my own personal experience it's like scouting, it's permitted (and even rewarded); it's a means to an end. However, there's little glamour and fewer 'educators' that know how to incorporate the same aerodynamic principles applicable to airplanes to model rocketry. I also believe there's fewer fields available, in addition to people seeing airplanes on a daily basis - while full-scale rockets are not viewed personally in public as often. Let's face it we pass by all sorts of airports, nearly daily, or see a plane in the sky. Few, if any, of the average population sees a full scale rocket daily; unless you're near a museum, NASA, or military facility.
P.S. Also, don't forget Trip's comments towards TARC at the last NARCON. Even with TARC going on for 8+ years now, the retention rate towards the hobby from students is almost non-existent.