Go on a half-day private tour of the must-sees in Riga with the best private guide in town (as described by his mother and some of his friends). Every city has its good, bad and ugly, and there's always the option of highlighting just one side of the coin. On this tour your guide will try his hardest to stay as honest and objective as possible, not losing the perspective of a local at the same time.
Four to five hours, including a coffee break, might seem long, but a half-day tour is the shortest possible way to cover all the most important sights that Riga's heart has to offer without a rush. Still - depending on your desire or availability, it can be longer or shorter - you can decide during the tour.
It's customizable as well, so if you'd like to drop a thing from the itinerary or add something different (eg, central market), the guide will be happy to adjust.