This is a definite problem for most of us. Having a friend or pet sitter come in would be the the most desirable, someone with aquarium knowledge better and someone with a saltwater set up the best (well almost the best, my son is in training for feeding all my tanks, is adult, lives with us and has his own saltwater setup - I do, however, pay him for the effort). You might check your closest pet store to see if any of the clerks would be willing to help out for a reasonable fee - assuming your parents are comfortable with allowing a stranger in the house.
If you have a small, locally owned pet store (particularly if you buy from them frequently) the owner might be willing to babysit if you have a set-up you can transport - provide your own water and food.
What are you feeding them? If you are feeding tiny shore shrimp or can get some (http://www.livebrineshrimp.com/
- write a note
to Phyllis that you need TINY ones for baby cuttlefish, there is a place for comments on the order form and she will take care of it without a problem but without a note the shrimp will be much larger) and be sure they will eat them before you go, you should be able to put a 4 day supply in the tank/net at one time. My two went through between 4 and 6 each day (we are up to 6 - 8 now). The count varies so I believe they would not eat them all at one time. You should probably sprinkle in a little
flake food for the shrimp and add some liverock with algae if they are in a net to keep the shrimp alive (fortunately, they will eat each other if there is a death or if they get too hungry but dead shrimp produce ammonia very quickly). If you have them in a tank with LR now, the shrimp should survive without supplement. If you are feeding mysis, I don't think this will work.
Good luck and let us know what you try AND the results.