If you want to explore Russia using the Trans-Siberian railway then you should allow for a few two or three day stop overs in some towns, like Krasnoyarsk. It's important to explore places like this in Russia, even if it's just to open your eyes a little. No, Siberia is not a hostile environment where only the remains of the gulags can be found. Far from it!
Krasnoyarsk is a pleasant and dynamic town with a lot of history. It has a very varied architecture, from an area of isbas (traditional wooden houses) to pedestrianised streets with facades that recall St Petersburg, and visiting it requires at lest a day. Perhaps, like me, you will be really surprised when you see the isbas - the area reminds you of the streets in westerns!
It's also a place with a rich artistic culture. Sourikov, one of the stars of the Wanderers, (a group of Russian painters) was born in the town. There is a museum dedicated to him and the guided visit is well worth it. You should also go to the Museum of Contemporary Art which is just as good as anything in Europe.
Then you'll be irresistibly drawn to a big yurt on the banks of the River Yenisei where you can try Russian and Asiatic food while sitting on padded stools. A good foretaste of the lands of Baikal and Mongolia.