On the Sonoma County side?
I've always approached it from Arnold to Dunbar.
I got to Arnold via Warm Springs from Bennett Valley. Bennett Valley can kind of suck if you aren't off peak, the only time I did it was in the TT at 6 AM on a Saturday. Are you going around the South of the Ridge to Sonoma? Arnold is definitely better down there.
If you're climbing from that side, there's also Cavedale, which I like better than Trinity, it's also been recently repaved, then it intersects at the top of Trinity. With Cavedale repaved, you could go up Mt Veeder from Napa, down Cavedale and up Trinity, and not get crashed by a pothole, but it's narrow so you'd need to take care on blind corners for traffic.
If you descend Trinity into Sonoma County, take some care on the top, some of the turns in the upper 3rd have some really nasty decreasing radiuses - SRCC stages a person with a skeleton at one particularly bad corner.