So, you find yourself On-Call

Key fob
If you have any security processes you must go through to gain access to your network, make sure that you bring these with you.  It won’t do to report to your boss that you left it at the office and cannot fix problem X until tomorrow. VPN or other secure access
Make sure you practice this connectivity from home.  On as many computers as you can.  From as many locations as you can.  Once I found myself unable to connect at home to the internet.  I ended up hijacking the wireless signal of a neighbor, sitting on their steps and connecting.  I’m glad that I had tested it on the laptop I was using, so that the scene of me sitting next door troubleshooting my database wasn’t any more stressful than it needed to be. Laptop
If you have a company issued laptop, make sure you have the means to carry it with you to all your favorite haunts.  I purchased a waterproof bag for mine so that I can take it on a boat.  I have a small messenger bag that I use to quickly haul the laptop around in my car.  This bag doesn’t have any of the excess items I normally carry with me to and from work.  Having multiple means of transporting this laptop makes it easier for me to bring it along wherever I go. I also configure another machine or 2 from home to be able to connect.  My personal laptop or desktop are configured, in case my work laptop is not present.  I practice often connecting with these machines to ensure success.  Just last night I connected with my personal laptop, even though my work laptop was with me.  I just needed to know I could do it. List of Servers
What are all the servers you need to access?  Do you have them all memorized in your head?  If not, you may want to simply jot these down somewhere to help you remember them.  I will often have a list of these servers in a spreadsheet with other pertinent information that is associated with them.  But do I remember to print it out and carry with me?