"Lunch

My coworkers and I have lunch together every day.
Usually we go by foot to the restaurant but it was raining today, so we went by car."

Almost perfect :)

Let's put it this way: you had a great intuition but you made a bad example. Let's suppose you wanted to say "Today he worked in a rapid way" then you could say "Today he worked rapidly" of course because you'd apply the adverb instead of the adjective. BUT, pay attention. Often adjectives and their related adverbs have different meanings: in your example you said "Today he worked hard" that means that he worked a lot. Instead, if you said "He hardly worked" you'd actually say the opposite because "hardly" does not mean "in a hard way" but rather "little" or "scarcely" meaning you'd say "He nearly didn't work at all" So remember, there are some exceptions, not all adverbs have the same meaning of their adjectives.