When I'm working I save lots of versions of a project. Every time I do any significant editing, or adding new tracks or, whatever, I do a "save as" with incremental changes to the file name (ver A, ver B, ver C, etc.) This causes me to end up with a lot of versions in my project folder when I am finally done with a project. Is it safe to simply delete these older versions?

Purely personal decision here. I do the same and never delete any of them. If storage is no issue, why delete them? cwp files use little space. Keeping them around doesn't hurt a thing. But neither does deleting them. If space is an issue, I'd Save-As the final version into another folder and then delete the original folder. This gets rid of all the unused audio files which take up the most space.

Hi. When I get a lot of cwp's of the same song, I usually make a folder for the older ones, and put them there.
Looks more manageable ,IMO.
All the best.

Yes, you can delete them but as others have written they do not take up that much space. Archiving them with something like zip may free up most of the space, tidy up the folder and still provide the ability to go back to an old version of the project.
 
To get rid of all the historical bits of a project perform a  "Save As" of the final project to a new location. When performing a "Save As" to a new location make sure at least "Copy all audio with project" is checked. This will produce a folder containing only the files related to the final project files. Then delete the old project file.

Thanks! It just tends to make each folder pretty cluttered and gets kind of confusing when I fail to do totally clear naming of each version. I am guilty of this sometimes. Ha ha!  

You can also make a backup to an external disc - and then delete your earlier projects and perhaps clean the audiofolder.

scook
 
To get rid of all the historical bits of a project perform a  "Save As" of the final project to a new location. When performing a "Save As" to a new location make sure at least "Copy all audio with project" is checked. This will produce a folder containing only the files related to the final project files. Then delete the old project file.

+1
This is my approach to this as well.
Just make sure you are clear on the process before you delete your previous folder. Make a test project and play around with the different procedures.