Should also mention... crowd noise will not be an issue. And, I'll be setting up on stage and will be able to position mikes anywhere for optimal signal... don't know if this plays into my query
In that case, you could use the DR-2d as a 4-track and do a soundboard/on-stage mix.
To accomplish this, set the mics up on stage, so they can pick up all the loud stuff that doesn't need to go through the PA (such as loud amps, possibly cymbals). Hook up the mics/battery box to the mic-in of the Tascam. (You may need an attenuator for this.) In addition to that, record a board feed through the line-in. That will take care of the vocals. Depending on where the console is located, you might have to run the mics through the snake.
I've done similar stuff with good results.