Short-circuit genesis_get_option to set Genesis options for a specific situation.

functions.php

<?php

// These are just two examples
// Uses anonymous functions since these are for one-time use

// Short-circuit genesis_get_option to show thumbnails
add_filter( 'genesis_pre_get_option_content_archive_thumbnail', function() {
  return 1; // 1 shows thumbnails
} );

// Short-circuit genesis_get_option to ensure we use 'thumbnail' for the thumbnail size
add_filter( 'genesis_pre_get_option_image_size', function() {
	return 'thumbnail';
});

// Short-circuit genesis_get_option to ensure we use full width layout
add_filter( 'genesis_pre_get_option_site_layout', function() {
  return 'full-width-content';
});