No, Santa Cruz County won't be.
I've worked with the County guys for going on 20+ years now, and they've looked at it. Santa Cruz county would not offer itself well to 700MHz. They already have a crap-load of radio sites to get what they need on VHF, having to triple or quadruple that to achieve the same coverage is well beyond what the tax base can support. They did play around with some 800MHz stuff, but gave up on it.
As for the APX, some cities have moved to them. I do think Santa Cruz SO has some APX radios as they needed something to replace a few failing XTS radios that are long past their prime, however rumors are that the sheriff officers don't really like them. A few cities have been buying the APX to replace radios as needed. It's very likely they'll be replacing most hand held radios with Harris XL models in the future.
P25 on VHF is likely in the future, existing repeaters/receivers are mostly converted over to Tait, and new radios are all being purchased as P25.
700/Trunked county wide will not happen in my lifetime.