Valle d'Aosta is Italy's smallest region — and it has the two biggest mountains in the Alps. SkyWay Monte Bianco (cable car to 3,466m), Roman Aosta (the arch, theatre, gate — "the Rome of the Alps"), Castello di Fenis (the most photogenic medieval castle), and Cervinia under the Matterhorn.
Each day is a logical geographic loop. Mornings for sights, afternoons for food, evenings for aperitivo. Car essential.
Day 1: Courmayeur + SkyWay Monte Bianco. SkyWay rotating cable car to 3,466m Punta Helbronner — Monte Bianco filling the sky. Panoramic terrace. Courmayeur town (Via Roma shopping + mountain food). QC Terme Pre Saint Didier (outdoor pools with Monte Bianco view, 55). Day 2: Aosta + Castelli. Roman Aosta — Arco di Augusto (25 BC), Teatro Romano (still used for concerts), Porta Pretoria. Collegiata di Sant'Orso (Romanesque cloister). Castello di Fenis (20 min — frescoed courtyard, the postcard castle). Day 3: Cervinia + Matterhorn. Drive to Breuil-Cervinia (2,050m). Lago Blu (the Matterhorn reflected — 30 min walk). In winter: ski 350km connected to Zermatt. In summer: glacier skiing Plateau Rosa or hiking the Matterhorn trail.
Best time: April-June, September-October (summer for mountains/beaches). Agriturismi/rifugi 60-120/night.