Learn Spanish (Latin America): Viajar en autobús es súper agotador.

In Spanish, when an action is the subject of a sentence, you must use the infinitive (viajar) rather than the gerund (-ando or -iendo). While English says "Traveling is exhausting," Spanish structurally says "To travel is exhausting."

How does súper work here compared to just saying muy (very)?

Súper is a colloquial way to intensify an adjective, acting much like "super" in English. It is more emphatic and informal than muy. While the Royal Spanish Academy (RAE) officially recommends writing it attached as a prefix without an accent (superagotador), in everyday Latin American text you will very often see it written as a separate word with an accent (súper agotador).

Does súper change if the noun is feminine or plural?

No, súper never changes its form because it acts as an invariable intensifier. However, the adjective it modifies still has to match the subject in gender and number. For example, if the subject were feminine and plural like vacations, you would say súper agotadoras.

Why do we use en for "by bus" instead of por?