I'm about to do another attempt at my SMB3 hack that I began awhile ago.  I originally had to abandon the project because of some ridiculous and unsolvable problems, but I'm ready to give it another shot.  I'm currently using SMB3 Workshop as the main editor.  Here are my questions.  Some are about this specific hack, while others are just general questions.

1. What are some common mistakes that I should watch out for when using SMB3 Workshop so that I don't run into any problems?

2. In the past, some of my levels would screw up when I edited different levels that weren't connected.  I would edit one level, then another would have misplaced objects and crash items everywhere.  Any idea what could have caused this, and what I can do to prevent it?

3. I want to get involved with editing music, but I don't know where to begin.  What programs should I use to get started?

4. When using Tile Layer Pro, what exactly are the areas that look like trash when you load a ROM?  Can these be used?

Any help would be appreciated.  Thank you!

1)  Never used, don't know

2)  no idea

3)  I think Sliver-X wrote a doc on the basics of music editing.  IIRC it's hosted here, just search for docs by author.  Only tool you'll probably need are a hex editor.

4)  Garbage graphics are code/data (ie:  everything in the ROM that isn't graphics).  No they cannot be used for additional graphics.

Forget programs (other than your trusty hex editor, and perhaps a tracker to auralize potential replacements prior to coding). I'm going to be releasing my comprehensive tutorial on SMB1 music hacking within the next few weeks. I suggest you study the standards and concepts within, then approach the SMB3 ROM with such in mind.

I'm still going for late January, which means six days...

It's at least 67% complete; more a matter of wrapping things up, dotting I's / crossing T's, etc. at this point.