Safety
Insurance policy is an essential part of all trips abroad. Do not economize on security because accidents happen, especially on a bike. Besides, you never know what disease you may catch during the expedition - for instance, a severe food poisoning. The cost of treatment abroad may be exorbitant.
Furthermore, I would like to warn everyone who is going to the mountains that reckless speeding is good for MTB marathons because there you only risk your own life and health. On the road, your bravado may have serious consequences. The stopping distance of a bike going 70 km/h, weighing about 120 kg (with the cyclist), is very long. Press the brakes too hard and you will end up in the middle of the road. Going into a skid is possible even on a straight road, a bit of sand is all it takes...
Although in Alpine countries wearing a bike helmet is not mandatory, I really recommend this safety measure. Helmet can sometimes be a nuisance (especially on hot days), but then you can wear a bike cap which protects your head from the scorching sun.

Our countrymen like to camp illegally because it costs nothing. However, this practice is banned in some countries (e.g. Austria, Switzerland), so it may get you in trouble with the police. The best solution is to ask a site owner for a permission to spend the night on his grounds or in his shed. If you really want to stay overnight in the woods, make sure that your camping is well-camouflaged and before setting off, leave the place clean and tidy.