I can tell you that traveling just as a couple can be just as nerve-racking. At least DH appreciates my planning when we get to our destination, and he does say thank you when we get home. But until we get out the door, I am a harried mess! And I have a hard time packing - I think its because I am afraid of flying.
To the OP - our petsitter brings in the mail for us, turns lights on and off, etc. You might want to see if you can combine some of your out-of-town tasks, to cut down the amount of coordination before hand. As for your sleepover company, I would let them know that it takes you a week to sort out laundry, mail, etc. when you get back from vacation, so you hope they will be OK with a disorganized, but happy house to stay in. Since it's free, they should be very happy that you are willing to welcome them!
Happy Healthy and Handsome DS 8/13