The problem for some employers is that their insurance or client requirements will stipulate certain minimum experience before they can let you loose in an IFR twin. IMHO a 300 hour pilot spending big bucks on the MECIR will need to also have enough cash saved up over the following 12 months to do a renewal. So then recent practice (or lack thereof) becomes an issue. More cash needed.
An instructor rating will initially make you more likely to gain employment.
I can feel an instructor shortage looming as the regionals and airlines raid the more experienced guys from the twin instructor jobs, with movement of the existing junior grade instructors into those twin jobs etc.
The alternative is to do neither, but spend the money on the big trip with a bedroll in the back of the ute to remote areas where you MAY get lucky and go straight into something like a C210 on charter or scenic flying. Because next year I believe that some of those operators will also see movement of their pilots into better jobs. Pilot demand won't be huge like it was three years ago, but it is starting to show signs of improving.
Good luck.