Since this would be just a vacation, the solar return chart for where you live is the one that really applies, because that's what you'll be living under for most of the year. Being on vacation somewhere else when your solar return happens might add a touch of the solar return house themes from your vacation, but the main themes of your upcoming year are still reflected in your home solar return chart.
Think of your solar return as a cake: the flavor and texture of the cake is where the planets fall in your natal houses and the aspects they make with your natal planets. The icing is the house placements of your solar return chart where you live. The house placements in your vacation solar return chart are a dash of sprinkles on top of the icing. They add a bit of new flavor, but they don't change the shape, texture, or flavor of the cake. With or without them, the cake is essentially the same.
If you moved to that location, instead of just visiting, it would be like changing the flavor of the cake's icing, but not changing the cake. Your solar return planets would still be in the same houses of your natal chart, and still making the same aspects with your natal planets, so the basic flavor wouldn't change, but if the house placements in your solar return chart changed, there would be a different emphasis in which areas of your life were up. That doesn't mean that what happens for you in the coming year would be better or worse, just a little different. Maybe you'd like one flavor of cake icing better than the other, but it wouldn't fundamentally change the cake.
In that light, neither chart can be better. Your solar return isn't a good reason not to go.
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