Hello!

Short summary:
We are two Swedish brothers who are going to travel the world in mid-January. We were hoping to collect an abundance of tips and information before we go, and where else to do this than with you folks who have already done what we’re about to do? Any help is greatly appreciated!

Preliminary route:
Our primary goal with this journey is to do adventurous things; we are going dive, climb/hike mountains, traverse jungles and deserts... et cetera.
We are planning to leave in mid-January, as aforementioned, so we figured Southeast Asia is a good place to start considering the season. We were thinking about starting out in India, then going eastwards through Bangladesh, Burma, Vietnam, Laos, Cambodia, Thailand, Singapore, Malaysia, the Philippines and Indonesia.
Thereafter we want to go to Australia and maybe island nations around Oceania depending on how expensive this is.

Depending on how much money we have left at this point, we have two alternatives here; either we travel to Central- & South America, or we go back towards Europe and Northern Africa.
By this time spring should be prevalent throughout Europe, so we want to climb/hike mountains and go snowboarding in the Alp regions. Also, we want to visit the Red Sea (preferably from Egypt and maybe Sudan).
If, on the other hand, we go to America, we want explore the Caribbean, and the South American countries of Peru and Brazil… at least that’s what our current thoughts are.

Our budget will probably be around 12,500€ (circa 10,500£, 17,000$) and we’d rather live and travel as cheap as possible to save money.

So here follows a series of questions:

Does the budget seem implausible even at first glance?
Is there something worth mentioning regarding the mentioned countries?
How exactly do visas work?
Are there any types of vaccinations worthy of consideration, except Hepatitis A & B, typhoid, Japanese encephalitis and of course tetanus? (Dengue fever? Malaria?)
We have been considering buying a smaller tent to bring with us, in case we come across places where we can sleep in that instead of a room. Any thoughts on this?
Any tips on hotels, motels, hostels etc.?
Are there applications for our phones that might come in handy?
Any tips on things to do and things to not do, in countries specifically or just overall?
What are the cheapest ways to travel around? Any decent guides or booking sites or such?
We both carry lenses. For those of you who know, how much of a problem does this constitute considering the fact that we will be spending some time in the wild? (We do have glasses of course)
How much of a problem will it be to not have a driving license?
What are good places to do parachuting and what is the price, approximately, for a tandem jump? (i.e., not with each other but with an ‘instructor’.)

For divers:
What are the best places to dive?
Any tips at all regarding diving?

For mountain hikers:
Any nice mountains (note that we enjoy a challenge, but we can’t climb with ropes and stuff)?
Regions to go hiking?

Any general tips on things to do? Places to go and see?

We hope you guys can help us! If there is something we’ve neglected to include, please let us know and we will update the post.

Regards,
Sebastian and Mattias