Verb conjugation of "durchhalten" in German

A proposal for our further cooperation: I will translate your texts in English and you translate my letters into Spanish. I will focus on spelling and grammar, and I will correct your sentence structure.
Sometimes I visit Vocabulix to meet new people. It is true that one could do the same on Facebook, but the FB page is rather for friends, and you are less likely to contact strangers for this purpose.
Have you ever visited the U.S. before and if so, where have you been in the U.S.? I've been travelling in California, it was very amazing. We have traveled by car. Here are my corrections.