Unfortunately, there are no configuration options that you can set to achieve this functionality.
You would need to create your own custom HTML input box and use the Juicebox-Pro API (specifically the showImage(index:int) method) to show the image corresponding to the number entered into the box.
You can see this in action in the Juicebox-Pro API online demo gallery here.
Enter an image number in the 'Show Image' input box and click the 'Show Image' button.
The code for this would look something like the following:

<script type="text/javascript" src="jbcore/juicebox.js"></script>
<script type="text/javascript">
    var jb = new juicebox({
        containerId: "juicebox-container",
        galleryHeight: "400",
        galleryWidth: "600"
    });
    $(document).ready(function() {
        $('#show').click(function() {
            var value = parseInt($('#index').val(), 10);
            var total = jb.getImageCount();
            if (isNaN(value) || value < 1 || value > total) {
                alert('Please enter an integer between 1 and ' + total + ' (inclusive).');
            } else {
                jb.showImage(value);
            }
        });
    });
</script>
<div id="input">
    <input id="index" type="text" />
    <span>&nbsp;</span>
    <input id="show" type="button" value="Show Image" />
</div>
<div id="juicebox-container"></div>

This might not be easy to integrate into a Drupal page, though.
You would likely need to be familiar with the source code for your Drupal theme and the Juicebox module for Drupal (which is an unofficial plugin note written by ourselves).
Perhaps posting your query in the Drupal forum (where those with more familiar with the module and Drupal itself will see it) might prove to be helpful.
I hope this points you in the right direction, though.

Edit:
If you are looking to for your 'Go To' button to select one of several different galleries (rather than to select a specific image within a certain gallery), then please see the Embedding Multiple Galleries support section.
Again, there is no quick and easy solution for this (you'd need to create your own menu links within your Drupal page) but the support section should at least help you to either link to different gallery pages or switch between galleries (using JavaScript) on a single web page. (Integration within Drupal might be difficult.)

If you are looking for a fully automated and customizable method of creating and displaying multiple galleries, then you might like to take a look at another one of our products - Showkase.

Showkase is a PHP web application (installed on your web server rather than your computer) which allows you to create a complete portfolio web site (integrating multiple galleries) online.
Showkase has full support for Juicebox-Pro and the galleries can be created within the application itself in a web browser interface (or created with JuiceboxBuilder-Pro and imported).

You can create Gallery Index pages and have as many galleries listed on each Gallery Index page as you wish.
Each gallery is represented by a thumbnail image with the gallery title displayed below and the gallery is opened when the user clicks on the image.
Demo sites created with Showkase can be found here and a sample Gallery Index page can be found here.
(Please note that although the Showkase navigation menu will include links for all gallery pages, there is no built-in support for selecting a specific image via an input box and this would still need to be implements manually.)

Showkase can also create non-gallery pages (About, Basic and Contact pages) where you can add information about yourself (or any other content you like).
All of this is done automatically within the Showkase interface without the need for any manual coding at all.
You can take a look around the Showkase interface by logging into the Live Demo Admin.