Well, I plan on having a slight backdrop. Roddenbury and Shatner will develop a good friendship after 1970 - the year the show ended in NotLAH (to make it interesting). Yet as the plague arrives- they will get out of LA, having the resources to do so. Shatner will head straight to South Africa, while Roddenbury will go to the UK, but as the situation gets worse there too - he joins Shanter.
Now Nimoy will head away from America to Oz when the plague arrives to try to get into production and stuff. He'll come to own a well-known tv company in Oz, from where he will become well off. Then hearing about the new Star Trek series, he'll come to see what happns.
Now Roddenbury died in 1993, but lets say he live a year or two more. So it will make it easier to get the show going, but once he dies - I'll have Nimoy take over his position. A result would be their budget would increase and the quaity of the scrips would get better and attract better viewership.