Can I just say "take a gondola", not "take a gondola ride"?
No, it would not be correct to say "take a gondola" here. If you said "take a gondola" in this case, it would imply that she wants to steal a gondola or physically get the gondola to keep. The word "ride" is necessary in this sentence because it goes with the phrase "gondola ride". "Ride" is the main noun in this sentence, so if you removed it, it would sound like you want to steal a gondola.