I would not call a region with a capital city that was founded in the 16 hundreds isolated.

Are you talking about the current capital of Medellin (founded 1717) or the original capital Santa Fe de Antioquia (founded 1541). Santa Fe sits on the Cauca river which was the only way the Spanish were able to make it that far into the mountains. It would take them months to travel to places like Medellin, which is why it was isolated.

Mestizo is just the spanish word for mixed person and fits all of Latin America as there are very few indigenous groups left.

I am using isolation in the standard meaning. To mean separated. I do not mean uncontacted. Sure uncontacted tribes are isolated, but so where the Paisas. What you may be missing is people didn't just take a day trip into this region. The Spanish empire sent groups of people with the wealth and resources of a nation state, forcibly using indigenous slave labor to travel deep into the Andes. Once they arrived, it was rare that people left.

The only way to get close was to use the rivers with human powered boats. Then you had to use established trails or cut through extremely dense dangerous forest. This kind of work took years to accomplish and was the result of generations of people slowly building up a colonized society at the will of the Spanish Monarchy. This is why most of the larger towns and cities in south weren't established until the 19th century.

From wikipedia about the Paisas: The Paisas have been considered a genetically isolated population according to scientific studies.

From wikipedia about Antioquia: Due to its geographical isolation, being located among mountains, Antioquia suffered supply problems. Its topography did not allow for much agriculture, so the city became dependent upon trade, especially of gold and gin for the colonization of new land.

I was in Medellin and Jericó two weeks ago. The isolation is talked about in the museums and is well established fact. I just mean separated not unreachable.