All of your choices are "idiomatic" if by that you mean they are grammatically correct. They could all mean different things though. The options that mean the action you describe would be 1 and 5. I'm also assuming that you know how to put these into the correct tense, as they are currently in simple present.
The main difference between "get up on" and "climb up on" is that the latter implies more effort as it describes the means by which you reached the roof. You can 'get up' off a chair.
Remember also that "climb on" something can mean that is the thing you used to climb, for example "I climb on the ladder to reach the roof".