If you are going to be off the grid while traveling, use this goodbye letter to let people know you won't be in contact.
Dear {Recipient},
As you know, I'm going to be away traveling for {number} months, and I just wanted to say goodbye before I head off. It's likely that I'm not going to be able to communicate much with you while I'm away, but I'll try to check my email every once in a while if you'd like to drop me a note.
I hope you know I'm really going to miss you while I'm gone. I'm sure we'll have a lot to talk about when I get back. You'll be in my thoughts, and I'll be sure to send you a postcard!
Best wishes,
{Sender}
