It's ~1890, exact date flexible. My characters transacted some business in Agra, and are fleeing India with trouble on their tails; I pick up the story just as they're about to board their ship home. Money isn't infinite but it's not a real limiting factor, and they aren't in a particular hurry to get back to England, they just want to get out of India, so they'll take the first ship they can get passage on that's heading in the right direction where a middle class European/American couple won't be terribly conspicuous.
My questions (and the answers to a) and b) probably affect the others greatly):
a) What port are they leaving from? Wherever they can get to fastest from Agra that has plenty of passenger traffic to/from England and with minimum stops in India after they board. It looks like either Karachi or Calcutta, but I can't tell which is more likely.
b) What sort of ship is it likely to be - i.e., just grabbing the first passage they can, is it more likely to be a large passenger liner, or can I reasonably have them on a ship with only a few dozen paying passengers and mostly cargo?
c) What port are they arriving in when they get to England?
d) Will they likely be making any stops along the way?
e) How long is the trip?
I'm assuming for daily shipboard life, I can carry over the stuff I've found about the Transatlantic crossing, but if I'm wrong about that or you have a good source, please do share!