Once you become a Ranker, you can use the staircase in the middle area to traverse floors (presumably this is that staircase Yuri and Evan were running down at the start of the story), but how long this takes seems to differ massively.
Quant and Leroro took most of 6 years to reach the 77th floor, yet Yuri managed to reach the 1st floor in seemingly minutes given she was traveling there specifically because of Baam's entrance. We could take this to mean Guides are super hax, but like you said, it looked like Yuri had only just gotten to the 134th floor at the part 2 prologue. The only logical conclusion I could then draw is that Yuri was really low down anyway, which makes no sense to me. It can't be that she knew Baam was going to enter like Headon did and was heading there since ages ago, because of the way she was talking about it to Evan. That or like you said, she just decided to show up on the 134th after doing shit all for 5 years, which would fit with what SUI said about the perception of time for Rankers, at which point were back to Guides being awesome.
EDIT: Actually, I just realized Quant and Leroro could have just gone really slow and made lots of stops themselves. I guess we just don't know enough to make any judgements.