Might be the best option because ...Contact Lionel directly and see if they have what you are looking for.
The 6-83716 number is the Loco.'s product number. And there isn't an instruction manual for the loco itself. On the Lionel support site, you need the set's product number to find it's manual.
Try this Link. It list the owner's manuals for similar sets. In fact most of the manuals don't mention road name, etc. as the operation is the same set-to-set (though a few are different for specialty sets, e.g. Area 51 RS-3 set).
There's a few more resources like instruction videos, beginners setup, etc.