Pune -> Mumbai on Bike...need route help

[rak007]

Hi Guys,
I am planning to take my bike to Mumbai (Borivali (west) specifically) from my residence here in Pune (Aundh). Please let me know which would be the best route.
One route that i am aware of (and thru which most of the buses ply) is

Pune -> Expressway -> Vashi -> Chembur -> Sion ->Western Express Highway -> Borivali

I know i cannot go through expressway and hence will take NH4 but rest of route remains same.

But i dont want to take this long route. I believe that there is a middle way (after highway completes) where i can directly reach western express highway from eastern express highway.

Please pour in your inputs