Longtime consider as the highest mountain on the planet, Chimborazo was dethrone by the Himalayan and Peruvian peaks. Nevertheless, considering the geometry of the Earth, this summit is known as the farthest point from it’s center (see section below for full explanation). This huge mountain is the highest point in Ecuador. It has five summits, the highest culminating at 6267 meters. There are many routes up its slopes. The normal route runs up the Southeast flank and is a variation of the original Whymper route. One can also climb from the East side (sun ridge route) which involves mixed rock/ice climbing.
The Normal route sees many attempts all year long and is consider a class 4 climb with route finding and crevasses crossing. There are two refuges on the mountain at approx. 5000 meters and most of the parties do their summit bid directly from the huts. It is a 6-9 hours climb with slopes up to 60 degrees. People usually start their climb around midnight and return to the hut in the late morning.
Fly to Quito and take a bus to Riobamba. There you will find good accommodations, restaurants and a lovely market on Saturdays. You can hire a taxi cab($15US) for the drive to the trailhead, 1/2 hour away from the Whymper Hut.
You can also stop at Ambato instead of Riobamba. It is more rustic but the accommodation is more complicated. From there you can take a bus towards Guaranda and stop at the lower trail head then climb up to the Whymper hut (16,250 feet) in 6-8 hours. Alternatively, as of January 2005, you can get public transportation to take you up to the entrance of the park, where you pay for the permit.
From there you have to hitchhike unless you have your private arrangement or are up for the dusty hike. From Ambato take a bus towards Guaranda, the driver will very likely know where to stop if you tell him where you want to go. If not, watch for a deserted house, painted with slogans, on the left side of the road; here you have to get off. (This house is also mentioned in the highly out of date and highly useless Bradt guide, which says you have to hike from here to the hut!)