You really don't want a heat lamp inside the cage for a snake. They get very hot and can really cause some damage.

If I were you I would research radiant heat panels(rhp). They seem to work especially well in wood enclosures. I have a few from ProProcdtucs and you can call them and explain what you have and what you want house and they will set you up with just what you need.

I heat pad commonly referred to as a under tank heat(uth) would not be a very good option in that cage. That said there are ways to go that route if necessary.

The size of the tank is a bit much for a young snake but you can make it work. You will have to add plenty of cover and hides to make the snake feel safe and secure. The wood is a good start but you would need to add some snake level cover like plants.