I am American citizen living in Mexico on a permanent resident visa. I am to marry a Mexican national. As we have no immediate plans after marriage to live in the USA, I assume a Visitor's Visa would suffice if, in fact, would be our only option. A related question is if, and when, we should decide we perhaps wanted to live in the USA, would it require me to be living in the USA for her to enter on a spousal visa? Thank you for a reply that will make me perhaps more confident of our plan of action.
I'll speak from personal experience. We are permanently resident in the UK. My wife, at the time an Indian citizen, was given a 10 year visitor's visa no problem. Our situation was basically identical to yours except we were married and live in the UK.
If you've been in a genuine marriage for more than two or three years, getting a 'green card' is likewise very straightforward and likely to be processed quickly as it was for us. You will not need to have an established domicile in the U.S., but they will ask for a address for certain contact purposes. I gave my mother's. Just keep in mind that the intention is that you will be living primarily in the U.S. They expect you to honor that.
For visiting, a visitor visa is appropriate, although being the spouse of a US citizen may make it slightly harder to get.
When you petition your spouse to immigrate, you will need to show that you intend to re-establish domicile in the US, at least by the time your spouse arrives in the US. You can go to the US together with, or before, your spouse.