Wed 3rd May-8th May-Visit Changbaishan from Dalian

I will visit China just after the Labour day holiday finishes. I will visit from Seoul. I want to see Changbaishan, is May a good time to see it? I am unsure how to get there in my short time(Korean holidays are awkward) and have found a lot of unreliable and conflicting information on how to get there. My flight will leave Korea at 5pm. Is it possible to get to Changbaishan from DL easily in that time and do the tour to Tian chi?

Where do I travel to? I would prefer to reach the mountain's nearest city by high speed rail or by plane if possible? Do I need to spend a night at the base of the mountain?