Headroom is the real obstacle
In the Tarentaise resorts the question is not whether a car can climb. It is whether the vehicle fits. The resort booking service publishes its heights: 2.15 m at Rhodos, 2.20 m at Hameau and Dou du Pont, 2.40 m at Rond-point des pistes, for roughly 725 covered spaces in total.
A transfer van already stands above 1.90 m empty. Add a roof box or ski bars and you clear 2.15 m without noticing. The consequence is easy to state: the structure is chosen before leaving, not at the barrier. That is also why we ask for luggage volume when you book, and not only for the number of passengers.
Moûtiers is the gate, the valley does the rest
Winter routing from the south runs through Grenoble, Chambéry, Albertville, then the RN90 to Moûtiers. That is where the valleys divide. Route measurement gives about 16 kilometres and some twenty minutes from Moûtiers to the resort, against 24 kilometres on the other side.
One documented detail: the Allues town hall bans parking of converted vehicles all year outside the Raffort car park, on public roads and municipal car parks alike. It does not apply to a sedan or a transfer van, but it tells you how tightly parking is managed locally.
When the train beats the road
Here is the case where we are not the right answer. For one person travelling in peak season, a full day of driving from the Riviera costs more and takes longer than a rail journey to Moûtiers followed by twenty kilometres of road.
The road wins back on three conditions, often met together: a group of four to seven, bulky equipment, and a flight arrival that connects to no train. That is the arithmetic we run before confirming, and we say so when it points the other way.