There is a lot of information in the MIDI tracks that you don't really need to play through a song, though it is important to creating a listenable midi file--Of course, many of the MIDI files that you find on the internet are done by people who are not professional musicians or arrangers, and they often have extraneous material in them-- It really pays to open the midi up in a sequencer program and strip out everything but once through each of the melodies(most tin pan alley type songs feature an AABA, I know, but in music notation, you just put a repeat after the first eight measures) and ditch all but the melody, base, and basic piano track(and even that often does just as well if it is stripped back to just chords)

A band can work up a great verion of a tune from the fake sheet, which may be from 8 to 32 measures of melody with the chords written above each measure. Unless you plan to take the time to actually orchestrate (note for note) a more detailed arrangement, you shouldn't have more than this (even the piano part that is usually written out on sheet music is usually unneeded).

Don't let the fact that you can fill pages up with music in that Noteworthy program lull you into thinking that you have actually accomplished something--even after you've converted a MIDI file, it takes a lot of work, and a fair understanding of music, to turn it in to a readable, playable document.