Hi pandology,
For #1, my suggestion would be to use something like http://wordpress.org/plugins/advanced-excerpt/ – in order to use that plugin in the events list you’ll need to make an override of the list template by making a copy of /wp-content/plugins/the-events-calendar/views/list.php and placing in an ‘events’ folder in your theme. Then replace the_content() on line 45 with the the_advanced_excerpt() function and the options you would like.
On #2, you should just need to change the post thumbnail size that’s being displayed. You can do this by making an override of /wp-content/plugins/the-events-calendar/views/single.php – again, make a copy and place in the same ‘events’ folder you created for #1. Then, find line 97 where the_post_thumbnail() function is called and add ‘full’ in between the parentheses like this:
the_post_thumbnail('full');
That should do it but let me know if you need any other assistance.
– Jonah