You need to look at this country by country, bud. Otherwise you could be sat in one country with that visa running out while you wait for your visa to the next destination. Even if you're planning to do the nomad thing you still need some idea of the visa regimes you're passing through. When I was researching my (sadly postponed) trip through central Asia I was surprised how many countries were either visa free to encourage tourists, or were visa on arrival. Others fairly easy and visas can be obtained on the road, Mongolia for example. Some are not, however. Russia for one which is quite restrictive and for which you need to go to an agency for the best chance of success and attend their embassy in your home country to be documented. Iran, China, Afghanistan, Turkmenistan, none of these easy to get into and some strict conditions may be attached.
The more research you do now they fewer problems you're likely to run into on the road.
fco.gov.uk is a very good starting point.
|