Good way to cook a roast

[Guest guest]

What is a good method to cook a roast that I can take with me on the

plane in little pieces in a ziploc bag (last time I took a couple of

ribeye steaks sans the fatty part)

I did chicken this way as well.

Any kind of yummy dipping sauce (I like avocado but I hate it if it

turns YUCK)

Any good method to bring cooked apples without it turning liquidy?

Thanks!

Jodi