I found a work around to the problem. But it took some work.
I downloaded as much as safely DL'd before it crapped out, 1.05 GB, but different people get to different spots. Then I made 2 "Cache 1 & 2" folders on my desktop. Then I copied the Installer from the application folder to Cache 1. I then had to go into hidden folders to find the app store download and copy the folder with the 1.05 GB file and the app store's manifest.plist file to the cache folder. This gives you a backup of the point you stop.
Then resume the DL. It will almost immediately fail. Quit the App Store. Go to the Application folder and delete/cancel the Installer file which will ask you if you want to cancel download. Then copy, don't move, but copy the manifest.plist and the folder containing the download back to the app store folder, keeping your cache copy. Lastly copy the installer file back to your applications folder. It will give you an in use message and hit continue.
You can now launch MAS and click download from purchases. It will say waiting but then start where you left off. Sometimes it will fail or have a problem immediately and you have to repeat the last paragraph. Other times it will resume. When you get through another chunk, pause the DL and repeat, alternating between cache 1 and cache 2.
I did this approx .5 GB per session, eventually getting it to complete.
By copying the correct files and replacing them after the error, you cab launch MAS and DL and it will resume where you left off. By not having to start over, you can incrementally complete the download. How much you add per copy session is up to how well the DL goes before problems.