24 hours in Bangkok - must sees / where to stay

Hi! My husband and I will be in Bangkok for roughly 24 hours this November. As of now we anticipate arriving on a Friday at 10:00, and leaving on a Saturday 14:00 flight the next day.

Where to stay: Current research is showing Sukhumvit near the intersection of the train lines - is this worth it even if it's a little farther out from what we're planning to see - Old Town, temples, etc.?

What to do: We'd like to see Wat Pho, Wat Arun, do a river cruise, and check out rooftop bars at night. I also originally wanted to go Khlong Lad Mayom Floating Market but it seems like that is too far away for such a short time. Is this insane / anything you'd cut and add instead?

Realistically, is a 14:00 flight the next day early enough that we won't be able to do much that day esp. if we are all the way out in Sukhumvit? (We will be flying internationally and are not Thai nationals)

Thank you!