Yes, you can refer to details from my Silk Road Trip, linked in post #3 above. This trip was in high summer--the heat can be worked around if you plan a break in the middle of the day to rest and rehydrate.

Main factual information that I know of for the areas you mention, that has changed since my 2012 trip:
--High speed rail is operating between Lanzhou - Zhangye - Jiayuguan - Liuyuan (for Dunhuang) - Turpan - Urumqi. This speeds things up considerably, if you can fit the timings into your schedule. [Note that from the Dunhuang in-town station, only east-bound trains are operating--westbound must go to Liuyuan by 2-hour road trip. This has not changed from my report.]
--Train tickets are purchasable 60 days in advance.
--Zhangye is much more well-known and likely will have more visitors. And I believe more upscale accommodation has come on line. At least in high season, there are now public buses going from/to central Zhangye to Danxia.
--Mogao Caves now require advance reservation, 1-7 days in advance for independent travelers. I believe the cost is now up to RMB 220 or 240. I hear that even the English language tours are getting fairly heavily subscribed. The online reservation website is not very user-friendly for foreigners, so try to arrange with your hotel to get in advance especially in summer. There is an in-town reservation/ticket booth where one can self-arrange.
--Entry fees at other locations may be higher than what I had in my report.