1.I cant help you on this one.
2.You get it at the border..check the validity dates though.
3. Main roads are sealed but can be rough...corrugations etc.
4. Get your visa before you go, tourist visa is 30 days max, you must state date of entry and exit as well as locations of both points. It is easy to get your "letter of Invitation" from St Petersburg International Hostel...www.ryh.ru
5.When in cities park the bike in an "Avto stayanka" this is a gaurded car park. Dont leave it outside on the street.
Do a search of Russia on the Hubb..lots of posts are available.
6. You can camp but lots of mosquitoes, guestinistas on the roadside are cheap. Dont
try to ride into big cities at night.
St Pete and its surrounds are sensational.
Close to Antarctica and a long way from reality