To help get you started: Just look at the HTML source of Super Search and put a similar form in your Free Nodelet. Include the "hidden" items. Replace any items that you want pre-selected with an appropriate "hidden", leave out items that you don't want to be able to specify (perhaps everything will be left out that isn't hidden), and you'll get a button that does the search you want.

For example, the following HTML:

<input type="radio" name="re" value="A" />
  Include <b>replies</b> from <i>any</i> section<br />
<input type="radio" name="re" value="S" checked />
  Include <b>replies</b> from <i>selected</i> sections<br />
<input type="radio" name="re" value="N" />
  <i>Don't</i> include <b>replies</b><br /><p>
[download]

Would mean that you would want to include the following HTML in your form in order to not include replies:

<input type="hidden" name="re" value="N" />
[download]