It’s 1779 miles from Hobbiton to Mount Doom.
I and some friends started keeping track on 24 July. It’s 458 miles to Rivendell: I got there in late October. It’s 920 miles from Rivendell to Lothlorien, and I got there mid-January. I’m now 1160 miles into the hike, and have a couple hundred miles to go before I get to Rauros.
Just over 600 miles to Mordor, something like four months. I’m a whole lot slower than the hobbits, although the pace has picked up considerably since the boxer arrived at the end of September.