I'm more of a dilettante on this subject, but I can point you towards some sources. Coe (1962) is pretty much a historical document itself at this point, but it's an interesting read on the cultural similarities he found between Postclassic Costa Ricans and Mexicans.

You can find broader interpretations of the region in Lange & Stone (1984) The Archaeology of Lower Central America and Quilter & Hoopes (2003) Gold and Power in Ancient Costa Rica, Panama, and Colombia.

To give a quick and dirty summary: The general pattern over time though, is small scale settlements primarily based around rivers and lakes in order to take advantage of seasonal flooding as natural irrigation for farming maize and other crops to supplement hunting and fishing. In the Classic era the area shows heavy influence from and ties to the Southern Maya region, particularly via trade goods, with distinctive "Olmec-style" jades and unique artifacts like flying panel metates. Weak social stratification is evidenced by larger houses associated with more elite goods, such as jade celts and pendants, with similar stratification in grave goods.

By the late Cassic, influence from South America can be seen in building styles (e.g., circular, rather than rectangular, foundations) and the introduction of metallurgy, particularly of gold. Moving up into the Postclassic, Mesoamerican influence returns along with signs of larger and more complex settlements like Las Mercedes, in Costa Rica, which had plazas flanked by circular mounds connected by cobblestone paths.

It's an admittedly neglected area of archaeology, but hopefully the sources I've provided can give you a starting guide to poke around further.