Here are my ideas:
Before traveling, look up online for as much information as you can, and email kosher stores to try and determine if they still exist, and the products they carry. Determine which chesherim (kosher certifications) are commonly used in that area, and choose those which you are willing to use. In addition, the phone number of a local Rabbi if there is one (or from the nearest large city) is invaluable.
In addition, check the customs laws for the country you are traveling to, and in they allow you to bring in salami, breads, etc. I have generally found getting kosher bread and meat (and chalav Yisroel for those who are stringent) more problematic than other products. But, for example, in Brazil the "kosher store" carried mostly tuna, meat, and sweets.
However, there are MANY things you can do or buy to make keeping kosher easier:
A. Pack in your CHECKED baggage a cutting board and a small knife. With these you can easily make salads and prepare fresh fruit. If taking a salami, take along an extra set of boards/knives for that. This last trip I took very thin plastic cutting boards which were basically weightless.
B. Be sure to carry some REAL non-liquid food into your carry-on luggage, especially since sometimes ordered "kosher meals" don't arrive to a flight. (Or in one flight, they served a "milky" meal 4 hours after a meaty one.) Even if the kosher meal arrives, it is usually rather unhealthy fare… Good food for carry ones are:
- "Mana hamah"
- fresh sandwiches (yellow cheese keeps well)
- pitot with a small (under 100 ml)(unopened) can of tuna
- a fruit or two. Cucumbers and carrot sticks are good too. (The fruit and vegetables you will want to finish before your arrival.)
- Good high-energy foods are raisins and nuts
C. Good foods for after your arrival:
1) -Packages of tortillas (stay fresh until opened, make a great wrap for tuna fish and salads), and for soya products
2) a WHOLE salami, unopened, the kind that does not need refrigeration until being opened (It might be problematic bringing into the US. In Brazil, no problem….)
3) packaged rice that can be cooked in an oven (double wrapping it in foil) or (if your Rav allows, in plastic in a microwave).
4) vacum-packed "swarmah" soya (needs no refrigeration until opened)