After attaining all of the ground team field qualifications, what sort of training would you recommend a CAP member pursue to improve their ground search and rescue skill set?
I'd say its more important, at least in a CAP context, to pursue mission activity to maintain proficiency and muscle memory.
I'd also work on setting up refreshers in things like navigation, procedures, etc. Our curriculum is fairly comprehensive specific to what we're allowed to actually do, so unless you're looking to extend your abilities beyond CAP, I don't know what else you'd pursue.
It wouldn't hurt to go after the SARTech ratings, but they won't mean much in CAP, at least not until they start normalizing our ratings against the national certifications.