We ahve done this before.
We have transfered from CBR to CSR
and
BWV to CR
The transportation guide will tell you to bus and transfer at the TTC
but we found that bussing to MGM studios or another park worked quite well
for us. As far as time that can be tough to judge considering time of year, time of day and how offen the buses are running.
I would say add at least 20 mins. on to your travel time.
-Kim