I was wondering what the best approach might be in moving source code, with history, from one Team Project to another Team Project. I am not concerned with work items, repo
Another option (and I think easier) is to import to Git then export back to TFS using the Git-TF command line tools.
Install Git-TF from binary, Choclatey or source code.
Clone a TFS folder:
git tf clone https://myAcc.visualstudio.com/mycollection $/TeamProjectA/Main --deep
Disassociate the Git Repo from the TFS server by deleting the .Git/tf folder and the .Git/git-tf file.
Configure the new Git Repo to connect to an empty TFS folder.
git tf configure https://myAcc.visualstudio.com/mycollection $/TeamProjectB/Main --deep
--deepgit tf pull
You should get a message at this point "git-tf: this is a newly configured repository. There is nothing to fetch from tfs."
git commit -a -m "merge commit"
git tf checkin --deep