many leave from maz. many leave from barra. some leave from huatulco and chiapas. folks pick n choose their departure points individually. is not a tight rally.
all mexican marinas i have encountered are safe to leave boats. it is what is done. eeny meeny miney moe... pick marina here you go. if in winter, aka high season, the cheapo pickings are slim. isla marina, mazatlan seems to be least pricey in short term situations , as price
doesnot vary for love nor water
buena suerte and bon voyages
ps ALL marinas in mexico have been militarized. ALL are well protected, not all have military guards, some do....but all are safe. now that marina mazatlan has locked gates complete with cameras, all are well guarded.