I just arrived in Almaty, after about 20 days crossing kazakhstan on the route you are about to go.
From Aqtau to Shetpe (small town 80 km from Aqtau) the road is good.
Then from Shetpe to Beyneu the road is in a really bad condition for about 200 km. Very dusty, with remains of tarmac. Mostly riding beside the road.
There is no gas station until Beyneu. Maybe in the sporadically appearing roadhouses they`ll sell, but don`t count on it. I had to load my bike on a truck halfway because of that.
The landscape is stunning though - totally flat, no one around! Perfect for camping.
Beyneu to Atirau is probably very good. Can`t remember really well, because I was given a lot of
s in the truck.
Atirau to Uralsk is good as well. You should be able to ride for 300km between the gas stations. Many of the small stations only have 92 octane.
Uralsk to Aralsk via Aqtobe: mostly good roads with stretches of gravel, due to road construction. Last Gas stations before Aralsk is in Karabutak.
From Aralsk to Shymkent are many dirt stretches due constructions, but you won`t have to worry about gas anymore.
Shymkent to Almaty is good, with few stretches, BUT more traffic controls. Have dollars in small denominations ready. `Straf` s are maximum 2000 Tenge, 12 Dollars.
Near the caspian days were warm and nights rather coolish.
In the north and center - Uralsk to Shymkent - days were coolish and nights sometimes very cold! Temperatures can change very quickly.
Strangely, near the Tien Shan I spent a comfortably warm night in my tent. Almaty was t-shirtable in the daytime.
Wish you all the best! This was my most intense riding experience in my 5 months travelling. Loved and hated it
now trying to sell the bike in Almaty.