When saying we like to do something, what do we do with the verb
that comes after "gusta"?

Honestly I would say the first one.

Explanation:

If you are saying its in present it's  "A mi me gusta el color rojo." Which means you like the color red. If it is in past tense you would say "A mi me gusto el color rojo." But if you are saying it in plural you would say, "A nosotros nos gustamos el color rojo." Which means we like the color red. Therefore if you were to say we like to do something, you would say gustamons .