Once Lydia has arrows to shoot, she's good to go, and I'll assume that she took the time to get them.<br/><br/>As a side note, she wanted<em>her</em>arrows back because they were cold iron tipped... they're a bit expensive when you add in the cost for the durable part.<br/><br/>If a way could be found to block the tunnels below and above, that would be nice, but my suspiciion is that there are other ways to get up or down, it'll just take longer.<br/><br/>As far as up and down, if you want to, Lydia has the dragon scale and it's another day, so 3 uses and more than enough lifting power to pull horses/injured up and down levels.