Maybe people here don't appreciate how far away the moon is, let alone the other planets, so let me give you an insight.
The distance from New York to London is 5470 km
It takes a healthy person 10 mins to walk 1km. Meaning to walk 5470 km would take 54,700 mins
54,700 mins is is 911 hours which is over 37 days of non stop walking. From earth the moon is roughly 70x further away than New York is to London so 37 days x 70 =2590 days to walk to the moon (just over 7 years)
Mars is roughly 800 x further away from earth than the moon is, meaning 800 x 7 years = 5600 years to walk to Mars. (As planets revolve around the sun the results may vary, but at time Mars can be the closest planet to the Earth.)
(Disclaimer- All maths done, have been done roughly and may vary. Distances are based on averages.)
Mars is way too small for us humans. It doesn't have enough gravitational force to stabilize our bones. So, living there for at least a year, would seriously weaken our bones. Plus, no protection from the sun. Solar winds could seriously injure us and destroy our constructions in a matter of days. Unless we wear special uniforms, we won't survive much longer that a decade. Also, no atmosphere. Venus on the other hand has an atmosphere. Only it's a chemical soup of death. It's also incredibly warm there, with toxic gases covering Venus' surface. But, NASA's plan to go to Venus (HAVOC), in wich we stay at a considerable distance from the surface of the Planet, thus avoiding the gases.
Here is some information so you can diced. Most of them are not planets but okay. The moon is a good first step to prepare for a colony on another planet. It is close compared to the others on this list. Mars is farther then vines, has a weaker gravity and not an atmosphere to that can protect us like most on the list but it is close to the sun. If we colonize Vines it is going to be in the sky. We would be able to practice on the Moon for a Mars colony and it is easy to set up a colony on solid ground. We could grow some poo potatoes ( I love The Martian) The general public has more interest in mars and we would be traveling away from the sun so we could use solar sails. Europa might have a under water sea so their is a small chance their is life their. It is far and has water as a resource. We could further study Jupiter plus solar sails :) They all have week gravity (except vines). Ceres is small closer then most of the other non planets. A good post a guess but other then that why would we care? As for Triton. Why is this on the list instead of Ganymede, Callisto, Io (o I guess maybe not Io because of the volcano) Titan and Mercury. Well its too far so maybe in the far future. Proxima B are we really capering apples to carrots. This is so random. Maybe in the far far future when we expand out of are solar system yea but soon not so much. It would be a good place to study another star. As for Pluto NO just NO. Maybe in the far future but it is small, far away like really far away little sun lite and just why would we want to? Most of thies are far from the sun but Vines is close and has days longer then its years so you would deal with that of little sun light. I wont vote except NOT PLUTO. Excuse spelling : ).
We should ask, critically and with appeal to the numbers, whether the best site for a growing advancing industrial society is Earth, the Moon, Mars, some other planet, or somewhere else entirely. Surprisingly, the answer will be inescapable - the best site is "somewhere else entirely.
Gerard K. O'Neill