I'm form Croatia and know a bit about this region so here goes (you didn't mention Croatia for your itinerary but I would suggest you visit our coast; I'm presuming you are traveling in the summer time):

1. You will need from 13 to 20 euros a night for a bed in a dorm in a hostel.

2. It is widespread in larger cities but it depends on what season it is. A lot of people go to the seaside and are not available for CS then.

3. Depending on how many of you are in a travel group, you would need about 20-40 euros a day for two self-prepared meals (pasta with some sauces or something) for 45 people.

4. For traveling locally, you almost never need a reservation but if you are traveling internationally, you will always need to book a seat or berth in a train.

5. 25 euros and up...

6. Perhaps budget for visiting museums, monuments, drinking, partying. Everything is more expensive in summer time and drinks are from 1.5 to 3 euros for half a liter of beer in a bar and from 3 to 5 euros for a 0.25 L bottle of beer in clubs...

7. I would suggest taking 1200 to 1500 euros per person for a months travel, including sleeping, eating, monuments and late night drinking every couple of days...

I'm form Croatia and know a bit about this region so here goes (you didn't mention Croatia for your itinerary but I would suggest you visit our coast; I'm presuming you are traveling in the summer time):

1. You will need from 13 to 20 euros a night for a bed in a dorm in a hostel.

2. It is widespread in larger cities but it depends on what season it is. A lot of people go to the seaside and are not available for CS then.

3. Depending on how many of you are in a travel group, you would need about 20-40 euros a day for two self-prepared meals (pasta with some sauces or something) for 4-5 people.

4. For traveling locally, you almost never need a reservation but if you are traveling internationally, you will always need to book a seat or berth in a train.

5. 25 euros and up...

6. Perhaps budget for visiting museums, monuments, drinking, partying. Everything is more expensive in summer time and drinks are from 1.5 to 3 euros for half a liter of beer in a bar and from 3 to 5 euros for a 0.25 L bottle of beer in clubs...

7. I would suggest taking 1200 to 1500 euros per person for a months travel, including sleeping, eating, monuments and late night drinking every couple of days...