Between Paris and the Chevreuse Valley, there are three possible ways to avoid the RER:
2. The "scientific" way: Porte de Châtillon - Bièvres - Saclay 🔭🧬🔬
It's the middle way (25 km), not too long, not too much elevation, which passes through the Saclay technology park 🔭🧬🔬.
The work on the Saclay plateau 🏗️ assumes that it will become more pleasant in the future, but for now, the proximity of the highways 🛣️ makes it noisy and sometimes dangerous, especially at the exit of Bièvres 💥🚧
The other two ways:
1. The "royal" way: Porte de Meudon - Chaville - Versailles - Toussus-le-noble 👑🏰🍀
3. The "flat" route: Porte de Gentilly - Antony - Massy - Orsay 🎺💫🛤️