The St. Louis region has a helpful page to explain how to add calendars to your phone or PC here: http://stl.pca.org/add-region-calendar/.  This will also work for the LTR calendar with the following changes:

Our LTR ICAL address is: https://calendar.google.com/calendar/ical/s52gdanf8jvh397ak62i9d2ars%40group.calendar.google.com/public/basic.ics

Our LTR calendar ID is: s52gdanf8jvh397ak62i9d2ars@group.calendar.google.com

You can also get to it with this URL: https://calendar.google.com/calendar/embed?src=s52gdanf8jvh397ak62i9d2ars%40group.calendar.google.com&ctz=America%2FChicago

You can also scan this with your phone:

 

When it opens on your phone, click the link at the bottom right with the + sign.

I have added Chicago Region PCA and St. Louis Region PCA calendars to our website as well.  They show up in the Central Illinois Car Events calendar on our events page.