First of all, be sure to bring enough money because Huashan is not cheap. From the main entrance where you buy your tickets (180rmb) you have to take a shuttle bus (20rmb/one way) to the cable car/stairs. The cable car was 150rmb (round trip) but gives amazing views and takes you half way up the mountains. Still enough walking/hiking to do after taking the cable car.
The mountain has stairs everywhere, so be prepared for that. There are no nature trails and it is extremely busy with mostly Chinese tourists. Drinks and snacks are available everywhere.
The views were amazing and definitely worth the effort to get up there. Some of the stairs are extremely steep and than of course there is the cliff side plank walk. This is optional as it does not take you anywhere. You will do it twice, as the way back is the same. It costs 30rmb and you'll be hooked up to a harness. Awesome experience!!
When I got back down the mountain I could not find a bus to the train station so ended up taking a taxi. You'll have to negotiate as they don't use meters in Huashan.
Both train stations in Huashan do not have much entertainment/restaurants etc. The Huashan Bei (north) high speed station is brand new but a bit dead. The Huashan train station for the normal trains is old with a few restaurants around it. There is also an internet cafe and a VIP area to wait which costs 5rmb and has comfy chairs.