With all due respect to a couple of previous posters, some kids just won't eat certain things, no matter how many times they are presented, or if you can creatively name them (broccoli trees), or if there is something to dip them in...they just won't. Trust me. I have two. Yes, I've presented the veggies, hidden the veggies (works sometimes), involved them in the process, etc. I've tried it all, more than once. Take heart, eventually, they may become more adventurous...(around 5 for my oldest, I'm still waiting with my younget).
That said, I used to take food for them to restaurants or on vacation--string cheese, easy-mac, squeezy yogurt, canned peaches, applesauce--go and buy a few individually portioned kinds of food that are easy to transport, and give him a couple of choices for each meal. He won't starve to death over a weekend, and you might be able to augment his choices from your plate (crackers, bread roll, grapes...). Little gladware containers are great for fish crackers, cheerios, blueberries, etc.
And good luck! It will get easier, I promise. I actually look forward to going away for the weekend now instead of dreading it like I used to! :-)
K.