Muy bien Kless, por nada o de nada ( its a common respond for a "Gracias", it means "youre welcome" eventhougt it translate directly to "for nothing" or "of nothing", trying to say "ohh you dont have to thank me, it was nothing" ;) got it?).
Que bueno que estas aprendiendo mucho en Rocket, MUCHAS FELICIDADES AMIGO!!!! (Its good that you are learning a lot with Rocket, CONGRATULATIONS MY FRIEND!!!
And yes, your expression "El viaje fue bien" sounded kindda wierd, but im sure any spanish speaking person would get the point !!!
"Estuvo" comes from the verb "estar" (to be)....and to be in past is "it was" or simply "was" so "Estuvo" means "it was" , but its also used to indicated something or someone in a certain position... "El estuvo en la fiesta" (he was at the party), "El estuvo en cama" (He was in bed or he stayed in bed")
in the case of "Fue" it comes from the verb "Ser", this also translates to "be", but its used in diffrent ways.
For example its not the same "I used to be a police man" that "I was a police man"....both sentences in fact say the same thing, but in a diffrent way...in the case of "fue" you can used it to translate the 2 english sentences.. "El fue un policia" or "El era un policia"....
BUT you cant use "estuvo" cause it doesnt make sence at all "El estuvo un policia"...cause it would say "He was at a police" pr "He stay a police" :S hahaha.
"Era" comes from Es (El es, ella es, ellos son,blah blah...)., which again it also has to do with "to be" , in i used it in the sentence "El era una policia" (he used to be a police man).
SO IN FEW WORDS...Era y Fue are almost the same, as in "he was" or "he used to be"....
And "Estuvo" has to do more with positioning something or someone at a certain place or time or in a certain condition "El estuvo despierto toda la noche" (He stayed awake all night long)...
Bueno, tengo que irme, nos vemos luego (Well, i need to go now, but see you later soon).