You hit the nail on the head - get on a shiup that travels the world - that is NOT Disney.
Also, if you want your job to be easy go where there are the fewest kids - that would be Holland or Princess.
The smaller, older ships of either of these lines are the ones that travel the most and have the fewest kids.
Here are more tips, while onboard learn new skills - shore-ex, for example, or cruise staff. That way you can work on ships that don;t have kids - the best, smallest ships.