The split below keeps the transfer in the morning, so the day never disappears entirely. Move the order if your flight lands in Paris, since the Loire is the closer region to the capital and the trip reads just as well north to south.
Day 1: Bordeaux on Foot
Start at Place de la Bourse, where the shallow water mirror in front of the facades turns the whole row into a second facade, and the old town opens up behind it. From there, the walk goes past Porte Cailhau and out to the Esplanade des Quinconces along the river.
Give the afternoon to the Cité du Vin, the museum that explains how the wine you will drink all week is made and labeled. Going early pays off, because every tasting after it makes more sense. If you plan two or three museum stops in the city, the Bordeaux City Pass comes in 24-, 48-, and 72-hour versions and covers transport plus discounted entry to more than 20 sites, Cité du Vin and the Musée des Beaux-Arts among them. For one museum, it does not pay. Otherwise, walk the quays at dusk and eat in the old town.

Day 2: Saint-Émilion, Then a Cellar
Saint-Émilion is the village people name when asked for the prettiest town in the Bordeaux region, and it earns the reputation in the lanes rather than from any single view. Leave early, book one cellar for late morning, and keep the afternoon for walking. One estate done properly beats three done through a windscreen.
In summer, the Atlantic beaches are the alternative, with the vineyards in full leaf on the drive out. Either way, be back in the city for dinner, because day three starts with luggage.
Day 3: The Move, Then Amboise
Take the morning train or leave the rental desk by mid-morning, and treat the rest of the day as a bonus rather than a full sightseeing day. Drop bags at the Loire hotel first. Then walk up to the Château d'Amboise, which sits on the hill above the town, the siting that many of the valley's châteaux share.
Clos Lucé is the second stop in the same town, and pairing it with the château fills an afternoon without a car. If the rail day ran long, take one of the two and eat early. The Loire's still whites come from Amboise downriver to Saumur, and a glass of one with dinner is the simplest introduction to the region.
Day 4: Two Châteaux and a Cave
Chambord in the morning, Chenonceau in the afternoon, and a cellar between them if the timing allows, since most producers keep a cave carved out of the local tufa rock and tastings there are usually free with no obligation to buy. Two châteaux is the realistic ceiling for a day that also includes lunch and a drive.
If gardens matter more to you than interiors, swap Chenonceau for Villandry and give the afternoon to the grounds. If your flight home leaves from Bordeaux, day four collapses to a single château and an early departure, and you should decide that before you book the return leg.
