How can I randomise location of objects in a room?

I solved a similar challenge by first creating an empty sprite that I could size properly - It is used basically as a 'Spawn Area'. Then I can simply instantiate objects as parents of this sprite, position them based on parent bounds (both by spawn area bounds and placement object bounds), and finally un-parent placed objects from the spawn area.

Some code sample:

 private void spawnOn(GameObject area, int amount, List<GameObject> items)
 {
     for (int i = 0; amount-- > 0; i++)
     {
         i = i > items.Count - 1 ? 0 : i;
 
         GameObject enemyInstance = Instantiate(items[i]);
 
         enemyInstance.transform
             .SetParent(area.transform);
 
         Vector2 spawnAreaExtents = enemyInstance.transform
             .parent.GetComponent<SpriteRenderer>()
             .bounds.extents;
 
         spawnAreaExtents = spawnAreaExtents - (Vector2)enemyInstance.transform
             .GetComponent<Collider2D>()
             .bounds.extents;
 
         enemyInstance.transform.position = new Vector2(
             Random.Range(spawnAreaExtents.x, -spawnAreaExtents.x),
             Random.Range(spawnAreaExtents.y, -spawnAreaExtents.y));
 
         enemyInstance.transform.parent = null;
     }
 }