I came across Kazakstan in late November 2004. I took the southern route from Almaty to Turkistan, Kizylorda, then north to Aktubinsk and across to Uralsk, crossing into Russia to Saratov, then south to Volgograd and Sochi. The roads in Russia were fine, but the road from Aktubinsk across the north of Kazakstan was the most difficult road i've ridden. A new road was under construction, but the detours to either side of the road were a quagmire of sticky, slippery clay with metre deep ruts made by trucks. The soil there is a fine clay, which is good in dry weather, but deteriorates rapidly when it's wet. Perhaps they've finished the road by now, there were no bridges when i was there, but if not, it really depends on the weather and the time of year you travel.