Northwestern Russia has long vied with Central Russia for political and cultural preeminence, first under the trading center of the Novgorod Republic, later under Peter The Great's creation Saint Petersburg. Saint Petersburg, having lost the capital status to Moscow under the Soviet regime, retains its popular image as Russia's Northern Capital, window to Europe, and in the eyes of many remains the nation's foremost cultural center for its unparalleled museums, art galleries, classical music, and architectural history. Just outside the city are three staggeringly beautiful and enormous Tsarist palaces at Peterhof, Pushkin, and Pavlovsk.
Not far from Saint Petersburg are a few other small cities with rich history—especially Novgorod, which is a must-see attraction for visitors to the region, but also Pskov and the twin castle cities of Ivangorod and Narva (Narva being across the river in Estonia). Further off the beaten path, but still possible as day trips from Saint Petersburg are small towns such as Staraya Ladoga, the birthplace of Russia, and Staraya Rusa, Dostoevsky's rural retreat, where he wrote and set The Brothers Karamazov'.
Far further from Saint Petersburg and isolated from major population centers are some of Russia's most important sights, which are hard but rewarding to get to. Kizhi Island, a tiny island in Lake Onega, is home to some of Russia's most important and beautiful intricate wooden architecture. Isolated and breathtaking fourteenth century Kirillo-Belozersky Monastery in Vologda Oblast, on the shores of Siversky Lake, was once one of the wealthiest landowners of all Russia. Solovki in the White Sea is a singular destination; once one of the mightiest monasteries in Russia, and fortress of the White Sea, Solovki was turned into a notorious gulag under Stalin's reign.
For the most adventurous travelers, the North Seas await. Arkhangelsk is the principal port for giant Russian icebreakers heading out into the Barents Sea and off into the Arctic. Expensive tours are available via these great ships, which can take you to some of the most isolated lands in the world along the Russian north coast, Severnaya Zemlya, Novaya Zemlya, and all the way to the Russian Far East to Chukotka, Wrangel Island, and off to the Bering Sea.
Russian is the native language of the majoraty of Northwestern Russia inhabitants. Important minority languages are: Finnish, Karelian and Veps languages in Karelia republic and Komi language in Komi republic. Almost all Finnish, Karelain, Komi and Veps speakers are bilingual and are fluent in Russian, aside from their native languages.
Basic English is widely understood in big cities, while in smaller cities and the countryside it can be very difficult to find an English speaker. German can also be useful. Older generations (over 30 years old) are less familiar with foreign languages than younger people.
The only international airports in the region are in Saint Petersburg, but far-flung Murmansk and Arkhangelsk both have domestic airports served by flights from Saint Petersburg, Moscow, and each other.
As noted above, Murmansk and Arkhangelsk have domestic airports with services between them and Saint Petersburg. In Arkhangelsk's Talagi airport lands a airplanes from Luleå (Sweden), Rovaniemi (Finland), Tromsø, Bergen, Kristiansund (Norway), Homel (Belarus) and Antalya (Turkey). Air travel works in a pinch, but the fares are high (while train fare is often very low), and you will likely have more inconveniences dealing with airport staff and what have you, than if you take the more standard overnight trains. If you are trying to get to Naryan-Mar in Nenetsia (good luck), air travel is the only plausible means of success, with occasional service from Arkhangelsk.
The principal mode of transport in Northwestern Russia (and Russia generally) is rail. Saint Petersburg is the undisputed rail hub of the region, and virtually all major cities in the region have rail service direct to the "Northern Capital." Southern cities also have direct service to Moscow. Given the vast distances throughout this sparsely populated section of the world, overnight trains are the most frequent mode of transport.
For intra-oblast travel, the most efficient and simple mode of transport are the electric train lines (Russian: электрички elektrichki. These small suburban radiate out from the main cities not just to suburbs, but to far-off smaller cities as well as small villages.
If the elektrichki don't take you all the way to your destination, you are in for an adventure. Buses and their smaller cousins (Russian: маршрутки marshrutki) connect the rest of the small towns and villages to the broader transit system. It is rare, however, to see a bus that has a clearly marked route. Often the only way to know which bus to take, and for that matter when to get off, is to ask. If you don't have enough command of Russian to do so, consider finding a tour operator to arrange transport to your destination instead.
High Arctic trip
Visit in Nikel city
Visiting Kola Super Deep Borehole and Zapolarny highlights
Short visit in Murmansk
Walk in Tundra Reserve or skiing in Kirovsk
Visiting Solovki islands
Visiting Pinega caves
Comming to Naryan-Mar
Visiting Nenets Natural Reserve
Trip to Novaya Zemlya (if it's possible)
Trip by train to Vorkuta