There is a very fine line between taking advantage of opportunities to carry out research versus being opportunistic! The former is reacting to circumstances that make the timing, viability of project or the set of potential co-authors available sooner then you might expect. The latter is doing a project because others appear to be successful in publishing in that area and you once had a vague idea you might like to do some work there.

Now you think you may be able to bluff your way through, but I guarantee that those of us around a little longer will see through the bluff! And we will remember the attempt to bluff even if you get lucky and publish the paper in a good home.

In the end you only have one reputation. To have a viable research career sometimes means not running after apparent low hanging fruit! Especially if you cannot tell really why it is a fruit and not a vegetable.