A thought about I-26: consider that the entire highway grid in that part of the country is rotated slightly to accommodate the shape of the Carolinas coastline. Look at routes like I-95, I-85, US 1, and US 17 - none of those run exactly north-south in that area, but they're all parallel to the coast. If a route like I-26 is going to cross all of those, it makes some sense that it should have an even number. Also notice the next few parallel interstates to 26 on both sides all have even numbers: I-16 to the south, I-74 and I-40 to the north. As a general rule, in that part of the country, "east" simply means "towards the ocean". (This is also why I'm not too bothered that US 52 isn't signed north-south in South Carolina, despite some areas of "eastbound" 52 running nearly due west.)
As for US 285: every time I'm in Denver, it throws me for a loop that in order to go to the mountains, which follow the west side of I-25 throughout the state, I need to go "south" on 285. If I were CDOT, I would switch the directional banners at Fairplay.