I think once you get the tradition JRPG airship trying to do requests is much easier. I don't get though why the unknown desert are is so tough, I haven't been back recently but I tried just before taking on Lambda and I still had to retreat. I had to use the light bottle to get to the ruins, which the enemies inside were much doable. I'm sad I used Pascal to do a puzzle, I thought she was just going to give me a small hint, not solve the whole thing.
I was at the top of the Lastalia Shaft, going in circles and I had to take a break because my mind wasn't doing any mental mapping. Did it last night and got to Fodra's core and stopped there. I was going to walk forward and just get to the next save point as it was late, but then I remembered it was longer and decided to hold off. I'm kinda happy I will have some enemies to go through, because I solved that eleth area puzzle beforehand to get one the Tales Tribute Weapons for Asbel, but the stats aren't as good as the other Tales inspired weapon he has.