I am now in the year 1200 and I think I have almost won.
I encountered a bug though.
I have 9 temples, 2 cathedrals and 8 cloisters (+3 temples and 1-2 cloisters under construction) - but still I fulfilled the "build 3 cathedrals"-uhv already. I mean it wouldnt be much of a problem for me to finish it (I took care not to build one of the cathedrals in my capitol so I can build one there in roughly 10 turns..)
I have the 10 provinces as well and am currently at 13k food with a production of around 250-300/turn (still increasing).
I think the most important thing was to find out that there is one hill where 90+% of the barbs will attack you. (see attached pic) So I posted my inital axemen there and later some spearmen.
My mounted archers went to meet and greet everybody

I think taking Kursk with the inital army is a very good idea, but I didn't do that and got lucky around 1100 or so, when there suddenly was only 1 spearman guarding it -> I still had 1 surviving axeman -> mine
However Nowgorod has walls and strong defenders!
I settled my 3 initals settlers in the Kiew and Podolia Area, the next one north (southern end of the smolensk province) where my 4th starting-archer was already waiting and then my 5th city was the one next to the stone, because I figured I need stone for the walls (and later saw that I need it for the cathedrals as well).
(in the pic the my starting cities are the ones on the left - meaning only the one in the upper right corner was build later)
From there on it was "build 1 spearman, 1 settler, 1 missionary and go build another city" in the main cities and "build worker, temple, walls, cornhouse, cloister" (in this order) in the new cities.
I find the provinces a bit strange...that I'm supposed to settle in unstable regions is okay, but why Rostow and Wologda and not Nishny Novgorod? Or Donasz?
Anyway the provinces I don't have are Novgorod (City with walls and 2 defenders one of which has 2city-defender-promotions), Wologda (too far north and is there any good spot to settle?) and Wolhyn....whatever it's name is. I figured I'd settle a useless city there just before the deadline but then I conquered a city in Rostow so now I'll maybe use it as a backup.
I went straight for "wood-chopping" (after trading my initial techs with Byzantium for all the basics

) and then knights (reached them around 1170).
I like the UU, even if I only used 1 of them before moving on to knights, but the UB seems useless. I mean it is a nice building...but you never have the time to build one -.-
I'm now preparing for the mongol onslaught and expanding to meet the food goal without difficulties
But I think that hill really was the important factor for me.
edit: stability...well I only started to care once I build city nr 10 or so, until then I hadn't build any stability-buildings so now I usually could build the manors (?) in 3-4 turns in my bigger cities -> stability so far is no problem..but I'll go and build some just to make sure, yeah
