Its been recommended on here on several occasiond before , try the free audio processor software Audacity. With the large file, cut into smaller files at natural breaks. number them sequentially and then rebuild. Though Audacity can handle quite big files, can your processor?
Hmm I have briefly tried Audacity before but if it does work better for large files then I will definitely give it a try. I know it is not going to be easy breaking up the files/tracks, especially MSEP. Each float fades into the next

At least that is the case with the track I have... I also have a very difficult time blending and avoiding bleeps or blurps when cuting and pasting.
One thing I have yet to get right is removing the Dreamlights intro narration and replacing it with the MSEP narration... Dear god that is hard to do! I know others have made edits, etc. On youtube someone posted the intro with the MSEP narration But they left out the most important part which is the full Wwweerow in the very beginning. I wanted to use the latest Dreamlights track as I like how the opening Wwwweerow has a better sound than on the original Dreamlights track or the MSEP/DCA track.