Well are you using a T-stat? If so, you can go with something like a 150 watt CHE. That's what I use in my 40g breeder tanks but I run them on a Herpstat and hang the probe under the CHE about 2" from the floor and set the temp from 87-88 so I get a cool side ambient of around 80. If you aren't using a T-stat, I would advise go to Home Depot and buy a lamp dimmer so you can adjust as needed. In a 55 gallon tank, I would probably get a 150 watt CHE and use a T-stat or lamp dimmer. Replace the red bulb with the CHE.

As for hides, check out Reptile Basics. They sell the ABS plastic box hides. I use them for my little sunglow girl and my pied girl and my pied girl loves them. My sunglow boa cares less about hides and mostly just sits on top of it at night haha.