I think Caucasus and the outskirts of Moscow. I might be wrong on the former and I just can't remember the geographical name of that region =/
Zaporozhye, Ukraine is the furthest documented travel I found when he met up with Manstein at least 3 times in 43'. Zaporozhye was Manstein's HQ's. http://www.vectorsite.net/twsnow_11.html http://books.google.com/books?id=5b...&resnum=6&ved=0CBUQ6AEwBQ#v=onepage&q&f=false http://www.theeasternfront.co.uk/timeline1943.htm
I know he visited some relatively (for him anyway) forward areas of Army Group Center. He made it to Smolensk in May 1943.