Actually, the first time in Buenos Aires we were using Marriott points for the flight down/back plus 7 nights at the hotel... have done that same thing twice to Spain and once to Australia/NZ. We have enough points to venture out again on that package, but don't have plans for that yet.
Haven't started working on things to do in either city -- will leave that to Mrs Deano (she's a soon to be retired Spanish teacher) so this cruise is sort of a retirement cruise
She's reading your posts as I make this reply! Once she registers on the board, you'll probably get some questions from her.
Nope, don't have a travel agent as we tend to do the arrangements on our own.
Dean