The Dreadnought was easy for a couple of reasons; it is a relatively large model, it is an “open” model type, and it can support a variety of LEDs as well as battery types. Now what I mean by an “Open” model is one that has a large internal cavity in which a LED or LED and Battery can fit. Even with fairly open models like the Dreadnought, you will still have to use a Dremel tool, sander, and modeling knife to open the cavity more, allow for the light to come through where you wish, and to allow the LED to sit in the right spot inside.
The next step is supplies: 18 or 22 gauge wire with LEDs, battery holders, solder, soldering iron, or wire cutters. This is where RadioShack comes into play. I do all of my shopping in store at RadioShack for a variety of reasons. The first is that I can talk to store reps to make sure that I am getting the right stuff. I can tell you that it is also a benefit to see the size of the parts so you can decide which would be the best to fit within the model. RadioShack also has solder, soldering irons, and great package deals like these on their website: Soldering Iron 1, Soldering Iron 2, Soldering Iron 3
Now these options are all depending on your budget, what tools you need to start, and how advanced you are in terms of electrical work and wiring. Wiring is going to depend on what you feel is going to give you the best result. I typically use 22 gauge wire due to its small size, and the ability to limit what the wires will look like if they are exposed. I will say that the last major hurdle is battery size. With most LEDs having a voltage drop around 3 V -3.5 V, it is going to take at least 1 to 2 CR2032 batteries to get the needed voltage. This is still without talking about battery holders which are going to determine if you can store a battery inside a model or if you have to mount it externally.
The coolest thing you get to work with though is by far the LED itself. It is what we are all about. How does the light enhance the model? How does it add that little bit to the model, and what does it do to make it stand out on the table? White light for a search light or to show a landing light, blue light to show a weapon coming online or a model coming to life, red light to show a corrupt soul or fire from an engine, or green light to show energy flowing to a deadly weapon; these are just a few options and opinions but the only limit on LEDs is what do you want to do with your model.
The last bit that you will need to complete the circuit is the resistor. The resistor will limit voltage and current going across the LED, it will protect your LED, and it will also allow for you to split the voltage and current across different LEDs. The resistor you will need will be dependent on your power source voltage, your current through the circuit, and the voltage drop across the LED.
This is the ledge; this is the jumping point; this is your first step into LED conversions.