I'd be sorely surprised if InDesign doesn't offer some functionality to easily allow shifting of all content before printing, exporting to PDF, or other purposes; but I can't find any sign of such a feature. This would be a useful feature, Adobe folks (hint, hint
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You might be looking for Layout -> Layout Adjustment. If all of your objects are snapped to guides, and then you turn Layout Adjustment on, and then change your paper size, then Layout Adjustment will (try to) nudge everything around automatically to fit.