In between San Pedro Sula and Tegucigalpa on the north coast, getting to Tela is fairly easy.

From San Pedro Sula:
There are a number of buses leaving from San Pedro east along the north coast highway.  Catch any bus heading to La Ceiba, Olanchito, or Trujillo.  They will let you off on the highway just outside of Tela and you can take a taxi into town for L.15.  There is also a San Pedro Sula-Tela express line. 

From Tegucigalpa:
Christina bus runs direct buses from Teguc to La Ceiba and Olanchito.  You can buy a ticket to Tela on any of these. 5-6 hours.

From La Ceiba:
Christina and Cotuc both make stops in Tela on their way to San Pedro or Tegucigalpa. 2 hours; L.60 (US$3)