Kanchanaburi

You can, but it's a long day. The drive is 2.5 hours each way, which leaves time for the bridge, the museum, and either Erawan Falls or Hellfire Pass, not both. An overnight stay is much better, especially if you want to swim at Erawan (allow 3–4 hours for the full hike) or try a floating raft house.

About an hour and a half up the 2 km path from the parking lot to the seventh tier and half an hour down, so allow three hours with swimming. Most visitors stop at tier 3 or 4. The upper tiers (5–7) are steeper and less crowded. Bring water shoes, because the rocks are slippery. Last entry is 15:30 and rangers start clearing the top around 15:00, so be at the gate by 09:00.

A section of the original line runs from Kanchanaburi to Nam Tok station, passing over the Wampo Viaduct, a wooden trestle clinging to a cliff face. The train ride takes about 2 hours and costs ฿100. It's one of Thailand's most scenic railway journeys and a moving way to understand the railway's scale.

They range from basic wooden platforms with mattresses (฿500–800/night) to comfortable resort-style rooms with en-suite bathrooms and electricity (฿2,000–4,000). Most are in the Sai Yok area, about 1.5 hours northwest of town. Expect no wifi and limited phone signal. That's the point.