Driving into Jana Pawla (city centre) Monday morning from the north
There'll be traffic, but if I were you, I'd come in along the Wisłostrada and then along aleja Solidarności at that time. Last time I tried the alternative via Marymont, it was a disaster with traffic, though it seemed more logical on the map.
You can also use the ratruns through Żolibórz, making sure to shout some abuse at a certain PF friend in the process ;) But I'm not sure if Mickiewicza will be jammed at that time?