[acecharly (OP)]

As a body approaches the speed of light time slows down.

We are moving around the Sun which in turn is moving around the Milky Way which is also moving.

So, if the Earth were to somehow leave the pull of gravity of any other body and we were able to observe the solar system from a fixed point, rotating and moving away from us on its journey around the Milky Way, what would be the effect on time, would it be the opposite to a body travelling at the speed of light? and would time last forever?

[greeniemax]

Time depends on the person observing it, thus if you are out of the earth and watching it from a distance you would see everything to be normal as time is same for you, your clock will tick exactly the same as it would on earth this is what you would notice, but because you have stopped moving it will actually speed up for you but you'd not notice (as I said before).

On other hand if earth has moved out of solar system and is travelling at speed of light (maybe I didn't quiet get your question), time on earth will will go to almost 0, people on earth will feel as if they aren't moving while you'll see that earth has moved from it's place.

[simplified]

As a body approaches the speed of light time slows down.

We are moving around the Sun which in turn is moving around the Milky Way which is also moving.

So, if the Earth were to somehow leave the pull of gravity of any other body and we were able to observe the solar system from a fixed point, rotating and moving away from us on its journey around the Milky Way, what would be the effect on time, would it be the opposite to a body travelling at the speed of light? and would time last forever?

Without experiment with check of relativity in inertial system of satellite we can't answer the your question.