Gado Gado is a mixture with cooked and raw vegetables, kind of like a salad platter, with peanut sauce for dressing.
What you need -- 3 cups cooked tiny potatoes; 2 long English cucumbers, sliced; 3 tomatoes, cut into wedges, or 1 box of cherry tomatoes, whole; 1 small cabbage, steamed and cut into 12 wedges; 4 hard boiled eggs, cut into quarter wedges; 2 cups of peanut sauce; 2 cups of steamed bean sprouts.
What you do -- on a large serving platter, spread beansprouts. Arrange cabbage wedges, tomatoes, and cucumber slices in a decorative way. Garnish with egg wedges and pour peanut sauce all over*. Add to your buffet for Rijsttafel.
*As an option, you could put the sauce into a serving boat, and allow people to add their own. That way you can have several boats of sauces, with mild to hot versions.