Well, the XNR (45m, 100 o2, 25m deco) cards are on the way.  Any certs beyond that have to be done out of state or pay an instructor to come to AR.  

The Rona screwed up all my 2020 plans, so we're planning a Mexico trip for May. I'm thinking about cavern or a 50m cert while there.

Any suggested instructors?
Or suggestions on places to stay? Currently looking at a few, but they're mega resorts. I like small.

A friend did her cavern through full cave with Natalie at Under the Jungle in Tulum (TDI), but they have the reputation for being the GUE of Mexican cave instruction. They have a very good reputation, though.

This is their SM equipment list - to give you an idea of how restrictive. Friend sent it after I shared my instructor's list (publicly available online) and was shocked at how unrestrictive it was!

https://www.underthejungle.com/wp-content/uploads/2019/10/SIDEMOUNT-COURSE-EQUIPMENT-LIST.pdf