Question please. I will be coming into the park this summer on highway 19/385, and leaving on highway 16. Will I encounter any road issues like tunnels, etc?
If you are coming in from the north, just don't make the mistake of going into Keystone and coming down 16A. Tunnels, narrow roads and a couple of pigtail bridges.
Coming from Deadwood/Lead area you are fine. Hill City to Custer City is good. Little steep as you come into Custer City, so don't be in too much of a hurry.
From Custer, you can leave east of west on 16, but 16A is not good in an RV.
Rent or drive your towed and see the area around there.
If you looking for a place to stay, Spearfish has a great park that is city owned and Very nice