There are international airports at Grenoble (Isère) and St-Etienne (Loire), and in winter there are flights from the UK to Chambéry airport (Savoie). At the time of writing there were flights from more than 20 UK airports to the four airports. Family ski holiday packages include flights and transfers.
As well as Lyon (three termini, including one at the airport), there are TGV stations at St-Etienne, Chambéry, Annecy (Haute-Savoie), Grenoble (Isère), and Valence and Montélimar (Drôme). You can buy combined Eurostar and TGV tickets with Eurostar; for advice and practical info see The Man in Seat 61 (maninseat61.com). In the ski season there are Eurostars from London to Bourg-St-Maurice (Savoie/Paradiski), taking 9/11hrs day or night (no couchettes, just reclining seats), with bus transfers to ski resorts.
If you drive, it’s a seven-hour journey by motorway to Lyon from the Channel ferry/Eurotunnel port of Calais.