1500 hrs. CFI, pipeline patrol, banner tow, parachute jumpers... whatever gets you the time (1500 hrs) quickest. Reread that - whatever gets you the time quickest. Nothing in there about "I'd like to...". The quickest way to improve your resume is to start flying a larger jet. That's most likely at a regional airline AND you get 121 experience which includes the training. Whatever gets you to the 1500 hrs starting line fastest is job #1.

"Everything else is rubbish." Manfred Freiherr v. Richthofen.