Depends on if your 55 gallon is horizontal (like a fish tank) or set up on it's side vertical like a vivarium (which is how you really should have it for tokay). You can heat with heat rope, or a UTH (under tank heater) or with a CHE (ceramic heat element). But so much depends on things like (as I mentioned already) the positioning of your tank, the ambient temp of the room it's in, if the lid is screen or solid, etc etc. Some people heat from the bottom, some from the sides, some from the top. Look through some old threads to see what others are doing.
As for hide, you want vertical hides, not hides on the ground. There's lots of great things that can be used as a hide. PVC pipe, Bamboo tubes, Cork bark tubes, cork bark flats, pieces of slate or other natural stone tile that are placed leaning against the side of the enclosure, heavy foliage plants, etc. The thing to keep in mind is that these animals DO NOT want to be on the ground. They want to be up on the sides or safely in a tube of some sort. Again, look through old posts for great ideas.