Wow, what horrible choices!
I held my nose and clicked Skiffy but I didn't want to.
Showtime - The audience expects Showtime series to be less mass market than Trek should be.
Spike - Cmon, Trek is better than that.
Skiffy - Has destroyed its reputation so thoroughly that Trek would be tainted by association.
CBS - Of all the major nets, this audience is the least good fit for Trek.
CW - This one has demographic problems, like CBS, but instead of too old, CW's is too young and too female skewing.
Cable in general has the problem of too-small audiences. Trek has been boosted back up into big-ticket franchise status by Paramount; CBS shouldn't be allowed to come along and smush it back down into mere basic cable status.
It's possible that CBS could sell Trek to another network. Fox or NBC would be the most appropriate. If it must be on basic cable, I'd opt for AMC, which is making a name for itself with quality programming that isn't too premium-cable-artsy/high toned.