I have no hidden or archived tracks.
Stop at project end is checked and selected.
What I do have are three envelopes which turn into dotted lines which extend 80 measures past the end of the song.
The envelopes themselves during the body of the song are all solid lines and end in a node.  After that, they continue as dotted lines.  I think that that is what is causing the song to play on.  
I have no idea why they are there and I can't figure out how to get rid of them.

Hi. To remove the node, you will have to open its properties "lane". Make sure all (red) is checked. Then you will need to find what parameters are being automated (blue). When in the right parameter, the line and nodes become active (and lights up). You should then be able to right click and delete the node(s). Hope it helps.

All the best.
Edit: The name of used automation is highlighted.
 

With all tracks selected, use the time ruler to select the area after the last event where the song should stop (where the dotted lines are), then choose edit > delete special and tick all options. 

Zarrg, the nodes are gone, I did figure how to delete them.  I still need the nodes and envelopes in the body of the song for automation, but after the song ends there is nothing.
Tenfoot, I did what you suggested and the song still goes on.
 
The only thing I can think of was that the original song was longer, so I selected all, put a split point, and deleted everything after the split.  I think this was the beginning of this issue.

jones082
Zarrg, the nodes are gone, I did figure how to delete them.  I still need the nodes and envelopes in the body of the song for automation, but after the song ends there is nothing.
Tenfoot, I did what you suggested and the song still goes on.
 
The only thing I can think of was that the original song was longer, so I selected all, put a split point, and deleted everything after the split.  I think this was the beginning of this issue.

If you repeat the process I suggested (zoom out and select a large amount of time immediately after the end of the song with all tracks sellected) does the delete special dialogue come up and allow you to make selections? If it does there is still some kind of data there. When it happens to me it is usually automation or a lyric, and is often long after the end oif the song, and  I have no idea how it got there. 

 
You're right, the dialogue box keeps coming up.
 
I  zoomed all the way out and I don't see any automation after the song and I didn't insert any lyrics or markers that I know of.
 
Is there any way to look for more hidden data?

Continuing to select and delete special usually works for me. Make sure all of the tracks in the project are selected (check track manager for hidden tracks) and all delete special options are checked.

Still doesn't work...just keeps giving me the dialogue box.
I'm going to try saving it under another name and deleting one track at a time and see what I find.

I found it!  It was a frozen track that still had measures continuing from before I made the song shorter.
The measures did not show up in the track view...they were invisible, so it was impossible to figure why the song was continuing.
 
Thanks everyone for your input.

Good news! That can be a frustrating issue to track down, but it is always hidden data of some kind.