How hot? Depends on the object itself- The geometry, the materials and how fast it's going.
How cold? Since there is no air in space, it would only lose heat by radiation so it would cool more slowly than it would on earth. Exactly how fast it cools depends on the geometry of the object.
Calculating the trajectory is in principle, fairly simple.
The time would probably take a couple of days, but it depends on how fast you go.
Essentially all of the energy is used escaping the earth. So it depends how fast you go, how big your object is, how much energy you dissipate in heat.
Once you get to a certain distance, the moon's gravity will pull you in the rest of the way. After you escape earth's gravity, almost no energy is required.
In principle, going to the moon is easy. Practically, it's much harder.