#query_posts = _your_doing_it_wrong
query_posts = _your_doing_it_wrong
as soon as you throw in that nasty query_posts you are killing off all the global variables and your paging will not work.
change:
query_posts( array( 'post_type' => 'fieldtrips', 'fieldtripcategory' => 'elementary-school-aquifer', 'order' => 'ASC', 'posts_per_page' => 1 ) );
if ( have_posts() ) : while ( have_posts() ) : the_post();
to:
$my_query = new WP_Query( array( 'post_type' => 'fieldtrips',
'fieldtripcategory' => 'elementary-school-aquifer',
'order' => 'ASC',
'posts_per_page' => 1
));
if ( $my_query->have_posts() ) : while ( $my_query->have_posts() ) : $my_query->the_post();
Also remove the wp_reset_query.