Russian visa registration

How should I go about my visa registration? I was planning on getting the hostel in Moscow to register me upon arrival and then have the hostel in St. Petersburg do the same. Is this OK?

Yes, that's okay. That is really all you need to do (register in both cities). Any valid and legal hostel should be able to "register" you, which you are encouraged to do. You wont need to register in Tver or Velikiy Novgorod because of your short one day stays. When you register, you simply show them the form you received when you entered Russia (a tiny form in your passport, keep it in there!) and the hostel will stamp it and record it in into their records. Anybody can "register" you, my wife registered me once at the post office and it took FOREVER!

Also, in order to obtain a Russian tourist visa you must have a sponsor. You can check with your hostels to see if they will offer you visa sponsorship. I once used the Hilton in Moscow and they provided sponsorship free of charge. Otherwise, you can just use a travel agency and give them your hostel details, pay their fee (usually around $25), they'll send you a stamped sponsorship form you'll need to send in with your Russian visa application.