Coba is the major Maya day trip inland from Tulum, and it feels very different from the cliff-top ruins on the coast. The old city is spread through forest, connected by sacbeob, the raised white roads that once linked its plazas, temples, and outlying settlements.
The distances inside the site are part of its character. Rent a bicycle or take your time walking between groups of ruins, listening for birds and the scrape of iguanas in the leaves. It is more humid and less breezy than Tulum's seaside site, so go early and bring water.