I think the least expensive route is Acapulco -> New Orleans -> Washington -> Ponta Delgada -> Lisbon -> London Not sure if you have enough money but there are trade goods on the route depending on seed, a fight with prize money if you can win it and a bible that you can get (depending on conversation choices) in Washington that usually sells in Ponta Delgada. If you get enough money to do this route, 10 days should be doable.

The fast route out of Panama is very expensive - not sure if slower routes out of there can be done in 10 days...