This lightbox works great! Especially with responsive design.
I was just surprised you keep the rel="lightbox[roadtrip]. It don't work with the W3C validator (at least when your site is in HTML5) where the class="lightbox[roadtrip] does.
So I changed the js and php files. And now it seems to work like a charm.
EDIT: Ok, it don't work anymore with IE (tested on IE8). Maybe I shouldn't change the js and php files.