With all due respect I have no interest in fantasy novels or role playing games. Time travel is just the setup for this thought experiment. Time lines, paradoxes, and notional understandings of the physics of time travel are pretty useless subjects for practical survival.

On the other hand practical survival in 1000AD is an interesting thought experiment. Dealing with technology, social structures and making the best use of a short list of materials and a much more extensive knowledge base most practical minded people in this age possess but fail to realize they have:

There is another thing a modern traveler might be able to do in 1000 AD. You would have significant advantages in navigation. The map you could draw from memory, assuming your map literate and reasonably capable, would blow virtually every map of the day out of the water.

What passes today as working knowledge of celestial navigation would put you in the upper percentiles of navigators and astronomers. They were still working out planetary motion. Latitude, asa practical concept, was understood fairly well by the best navigators. But longitude was a complete mystery. Just knowing how it was solved, by use of accurate clocks, puts you ahead of every navigator of the day.

So much better if you have a watch.

Add to this an understanding of nutrition and vitamin-C, a problem that would be the scourge of oceanic navigation into the 1700s, and food preservation and water collection and you could be the single most capable seaman on the planet at the time.

Remember that Columbus was looking for India when he ran into the Caribbean and Cuba. Which is why we call native Americans Indians. You might not know a lot about geography but you know rough where North and South America are. You know were Australia is. You know about the isthmus of Panama. In broad terms where Japan and Korea are.

Given a choice getting to a port and signing on as navigator might be a good move. Possibly working for a mapmaker. Knowing the alphabet and numbers would be a major benefit. Ports were less well traveled by clergy and they were, by reputation, more tolerant of differences and peculiarities. A large muscular, overly clean, effetely soft, person who could read and who has strange manners and customs might not stick out so much.

Funny thing is that if you know something about seagoing boats in modern times you wouldn't be unfamiliar with the boats of 1000AD. The basics haven't changed in a thousand years.

For those who don't think thinking about living in 100AD has any practical value you might remember that navigation is a practical skill. If you could get along as a navigator in 1000AD you could pretty much make your own working tables and instruments and navigate in a survival situation today.

For long-term survival the practical aspects of food preservation and nutrition are the same as in 1000AD. As are the aspects of getting along in a radically foreign culture. Dropped into the tribal areas of Afghanistan could see you having to get along with practitioners of a harsh religion where inadvertently insulting their faith, or advertising yours, could be fatal.