Rio Bravo takes up the coastline of southern Texas with some of northern Mexico. In fact, it's a pretty small kingdom concentrated on the coast in a zone filled too much with raiders.
To the north lies the rest of catholic cristendom, with 2 duchies on the border, to the west and to the south only Sagrado Corazòn followers and mictlantecs are present. To the east, the Gulf of Mexico
Probably one of the worst kingdom rank starts. There aren't small realms ideal for feeding, only domains as large and powerful as you, the only Catholic in range to help for a holy war are small duchies and Comancheria is too far away. The ruler also is weak compared to its vassals, factions can be extremely dangerous as well
AI Rio Bravo is not going to survive in a normal scenario. Too many enemies are at its' borders, and within. The crown of Rio Bravo is as fragile as that of the Caribbean Empire, and soon the player will see a fragmented group of duchies and counties. Not even if the Pope calls for a crusade for Jacinto and not for Louisiane the downfall of the kingdom will slow down.