Near Perdasdefogu there is a launch site for military and sounding rockets . Unfortunately it seems to be impossible to get informations about launch dates and there seem to be no possibilities to view the area.
The same rules apply as in Italy.
There are airports near Cagliari, Alghero and Olbia. See below for some links.
There are ferry services to Cagliari (south coast), Sassari (north coast), and Olbia, Arbatax (east coast). See below for some links.
You may need to hire a car (una macchina). Beware the way locals drive: racing along the narrow and bendy roads in the hills.
Regular, cheap buses between the main centres: Cagliari, Sassari, Alghero, Nuoro etc. You may end up changing buses (or trains) in Macomer. Less frequent buses, but worth persevering for the smaller villages.
Regular trains from the edge of Alghero to Sassari and from Sassari to Cagliari, although buses are usually quicker. Change at Macomer for trains or buses to Nuoro. Less frequent trains on this and other routes.
In the summer period, twice a week, there's a small train that travels from Sassari to Tempio and back. It runs especially for tourists and is highly recommended.
Mirto is an alcoholic drink that's a local speciality.
Campsites: There are many Campsites all around the coast, most of them close at the end of September or early October, but some are open around year. Prices get as high as 30-40€ in the Mid-Season (August) for a small tent, car and 2 people and tolerable in September/October to an average of 15€ (3-star-campsites).
For some serious night life, you obviously have to go to the big cities or the tourist beach places. In the small towns, the young people will get you to join in with their drinking games. You should join them since there's nothing else to do there anyway.
The oldest and most famous web site about Sardinia is Sardegna.com. Here you can book your vacation in Sardinia.