Some questions for any Drilling/Petroleum Engineers

I am a senior MechE student and am interested in getting into the oil business. The lifestyle and paycheck both seem pretty interesting to me, particularly engineers that work a rotation on the rig. It seems like it would leave plenty of time for me to travel, not to mention be able to work in locations around the world. Working in places like Africa or Russia actually seems pretty cool to me.

I had some questions for anybody who has more knowledge about the business.

I have heard that I would have to work for a service company like Schlumberger or Halliburton for at least 2-3 years before a major would even consider me. Are the conditions in these service companies really that much worse than a major?

When you are off rotation, is it actually like a mini-vacation or do you still have to be on call/report to an office?

What is the career progression like? Field engineer at service company for 3 years, drilling engineer for 5-10 years, then office job for the rest?

Any other tidbits of info would be appreciated as well.