Randall Frakes came back to do novelization for the second film. This one is different because it is mostly script which well, even according to the writer, was so full and so well written it didn't require much addition of embellishment.
Randall Frakes: For TERMINATOR 2, I wrote everything. It was more work, but the script (co-written by Jim and Bill) was so detailed and so good, that it was easy to transform it into a novel. My adds were either directly inspired by the script, or came from early discussions I had with Jim and Bill. (JCO interview)
The novelization includes an extended opening future war sequence in which the resistance sends Reese back in time and accesses Skynet's storage to reprogram the T-800. It also features the coda ending of elderly Sarah in the park, watching adult John with his daughter
It sold really well and also boosted sales for the novelization for the first film again. The T2 novel is widely available for good prices
Go back to http://www.jamescamerononline.com/TerminatorTrilogy.htm