I think the other posters have already covered the main points, but I’ll chime in and say that as a general principle, there’s no such thing as a “no go country.” You can go places that might take you away from being able to go to Mass. So long as you didn’t go to Saudi Arabia to avoid having to go to Mass, then there’s nothing wrong with going there, or anywhere else where Mass attendance might be difficult or impossible.
Dispensations can be given at the discretion of the one empowered to give them. Some are very zealous about not giving them, whether for the Sunday obligation or anything else. I think in general it’s better to give them wherever there might even be the hint of a cause to do so. It’s better to be generous in this regard. There’s a canonical principle that says that favors are to be multiplied and burdens restricted. While this literally applies to how we interpret penal sanctions, I think it’s a helpful way of looking at pastoral practice. God isn’t a petty bean counter who’s just looking for an opportunity to whack you because you didn’t check this or that box. If you’re making a sincere effort at following him in the way he calls us to in his Church, that’s the key. It isn’t only about following the rules, and sometimes the rules get relaxed, even for only very basic reasons.
As for it being dubious that you wouldn’t need a dispensation, that’s no dubious at all. If you can’t go to Mass, you can’t go to Mass. An obligation cannot be binding if it would be impossible to fulfill, or even very difficult. You don’t have to confess missing Mass due to illness (yours or that of one you’re caring for). You don’t have to confess missing Mass because the weather made the roads unsafe. Going to Mass isn’t an absolute good that we must move heaven and Earth to do. There is an obligation, and we should make a reasonable effort to fulfill it. We shouldn’t blow it off lightly. But the flip side is that we don’t have to kill ourselves to fulfill it, nor cease living our lives.
-Fr ACEGC