The 2 times I've been we transfered straight to Arillas, however the last time we did bugger about in Arillas before getting to the Rainbow, the journey seemed to take for ever but as about an hours.
Going back we had the first pick up both times and then had to go via St. Stephonos, Rhoda, and so on... still it meanrt we didn't have to hang around at Corfu airport... both time we were late arriving so it was straight in to check in.
Have fun either way.