Since I need to carry everything with me, it does not make sense to just throw unopened packages into a box. Besides, some things take a bit of time, so it's best to get them out of the way up front.
So I do what I can at home early in the week. It really does make the actual cooking event go a lot smoother.
A great example of this is turkey stock. I greatly prefer proper freshly made stock to anything I could buy, but trying to make it at my in-laws' house would be a great strain.
Making stock is simple. You need bones, and maybe meat. You need three core vegetables, and you need some spices and herbs. Finally, you need time. Here's what I put into mine:
Eight turkey necks
Two really big onions
About six stalks of celery
Five or six medium sized carrots
One head of garlic
A few bay leaves
A couple of teaspoons of cloves
A couple of teaspoons of peppercorns
Turkey necks are abundantly available just before Thanksgiving, and are great for making stock. I first browned them in olive oil, but you can roast them, or just leave them raw. I prefer a bit of browning personally. If you have access to carcasses, or to backs, or a bunch of wings, that all works well too. The main point is to have a bunch of bones in the pot, because a big part of good stock is the gelatin we extract from them.
Once the meat is ready (and browning in batches takes time), it's time to get everything else into the pot. I cut up the vegetables into pretty sizeable chunks, and cut the root off the garlic. Everything went into a big stock pot and was covered with water. I actually miscalculated and used too small a pot at first, so I had to transfer it all to a bigger one. That was not a lot of fun.
Bring this to a light boil, then put a cover on the pan just a bit askew, so some steam can escape, and bring it down to a simmer. It should be left that way for at least a couple of hours, but longer would be better. This year I simmered mine for about nine hours and it turned out to be absolutely lovely.
Then of course, you need to strain it. You can use cheesecloth, but a few years back I spent the money to get a chinoise, and I have never regretted it. Use it, wash it, put it away for another time.
This is basically no more than a very large and very fine strainer. It's also strong enough that you can really press the contents hard to extract every bit of the valuable liquid. And you do want all of it.
When it was all done, I had a pot with nearly two gallons of unctuous, fragrant stock, ready to cool off and transfer into smaller containers for transport once the fat was skimmed off.
Go ahead, make stock for yourself. It is not difficult, nor is it even really that time consuming. You can go about with the rest of your life as it simmers along on the stove top. It is a basic ingredient in many dishes, and nothing you can buy in a store compares. It freezes very well, and if you've got some you're ready to make soups, sauces, or just the best rice ever.