Olé! Olé! Olé!
(I'd be interested in watching such a run, but I don't know how much of a help I'd be on route planning)
Edit: just throwing this out here as a starting point. I expect it's all kinds of flawed. I'm assuming you don't use any out-of-bounds traveling, too, which means the
map is actually useful.
Basically work your way around in a clockwise circle, starting with Creaking Skull, then Big Golem, Headhunter, etc. After killing Manticore, it might be worth teleporting back to the beginning and going down to the Arena and Underground Cemetary, then getting to Great Armor via the Forbidden Area (Julius can get through the waterfall with careful use of the backdash, right?). This would replace the run from Manticore to Great Armor with a run from Legion to same, which I
think is worthwhile. If it isn't, then you'd tag Great Armor and then backtrack to the chapel teleporter before doing the arena/cemetary run.
There's a pretty big "lag" (lack of bossfights) between Death and Manticore. Fortunately Manticore itself is right near a teleporter.
Edit: duh, if you have to go from Great Armor to a teleporter anyway, you might as well go to the Chapel one and kill Manticore on the way; thus, after killing Death you'd teleport and sweep the lower half of the map.