How is this a repeated question? You haven't posted it in this forum before.
If you still live in the city where you were born, cast your solar return chart for that city. If you live elsewhere, cast it for where you currently live. Location determines the houses, and where you live is where the influences you'll be living under all year are.
If you're traveling when you have your solar return, the solar return for your location during your trip reflects what's going on during your trip. That adds a little extra flavor to your home solar return chart, but it's not the main determinant of what's going to influence your year.
No matter where you are, the planets at your moment of solar return will be at the same zodiacal degrees, making the same aspects to your natal chart, and in the same houses of your natal chart. That's most of the chart right there. Travel doesn't change it. It's like a cake, which has the same basic flavor and texture no matter how it's decorated.
The solar return houses are like icing on the cake. A different kind of icing may make the cake taste a little different, but it doesn't change the flavor of the cake.
If you go on vacation for your solar return, that's like adding sprinkles to the cake. They don't change the flavor of the cake, they don't change the icing either, but they add a new note.
So if you want that new note, feel free to take a birthday trip. If you were going to travel for your birthday anyway, apart from astrology, go ahead. But don't expect it to change what your solar return chart is telling you.