It's hard to make exhaustive lists of verbs and their matching prepositions.
Prepositions depend your intention. I can only suggest that you practice a lot.
Just a little note: "Andar/estar de viaje" (to be on a trip) is not exactly "viajar" (to travel).
· Anda de viaje
por Ecuador. -> She's travelling somewhere around Ecuador.
· Anda de viaje
en Ecuador. -> She's travelling in Ecuador.
(Similar ideas, but I'd say "por" is a bit more vague.)
"Viajar" can use: -a, -por, -en, -con/-sin, -desde, -hacia, -hasta, -para...:
· Pedro viaja
a Berlín esta tarde.
Pedro is travelling to berlin this afternoon.
· Viajaron
por toda Europa en 30 días.
They travelled around Europe in 30 days.
· ¿Viajaste
en tren o
en autobús?
Did you travel by train or by bus?
· Juan viaja siempre
con/
sin su esposa.
Juan always travels with/without his wife.
· Mis padres viajan cada año
desde Canadá
para visitarme.
My parents travel every year from Canada to visit me.
· Empezamos viajando
hacia el norte, pero luego nos desviamos del camino.
We started the trip to the North, but then we turned away from the road.
Hablar de/acerca
de (algo/alguien):
· Estamos hablando
del/acerca
del calentamiento global.
We're talking about global warming.
· ¿Estás hablando
de/acerca
de mí?
Are you talking about me?
There is also "Hablar
con (alguien)":
· Hablé
con el director de la escuela y dice que no estás yendo a clases.
I talked to the school principal and he says you're not attending your classes.
· Habla
con tu esposa para que te perdone por lo que le hiciste.
Talk to your wife so she'll forgive you for what you've done to her.