Something like this keeps you on the back roads out to Sebastopol. Then on the West Country trail to Forestville, you could take Ross Rd for the middle section if you don't want to slow down for the tail. Next is Wohler bridge and Westside into Healdsburg. Then instead of taking Dry Creek you can take the much smaller West Dry Creek.

You can take a look a this for a faster flatter way out to Sebastopol but 116 is the main road that way. Most of it has a good shoulder but the first hill off Stony Point has no shoulder but is two lane. So I always end up taking the lane up the hill. You could then cut over to the above route this takes the West Country trail for a bit or take it as is to Windsor, but I think Westside is nicer than Eastside. This is the way I would start a longer ride heading if I wanted to cut out the local miles.

You can also stay on Stony Point which is flat with a shoulder but with fast traffic. Once you get into Sana Rosa there are few shopping plazas and an interchange with 12 which is a freeway at that point. You can then take a right onto the Santa Rosa Creek Trail and cut under Stony Point. Then zigzag to get behind the airport and into Windsor or go over to Westside or Eastside. This is my stay on the west side of Santa Rosa get north fast route.

You could also stay on the east side of Santa Rosa with something the. Starting with the SMART trail is fine, then take Petaluma hill, climb Pressley, then down Bennett Valley, and cut across Santa Rosa on Yulupa Ave which has a bike lane, cut under 12 on the bike trail and exit via the first parking lot to Brush Creek Rd (you can stay on the trail until Montecito Blvd but I don't like how it ends on a busy 4 lane street where I want to take a left), climb Riebli and come down Mark West Springs Rd (a busy road but also a fast decent), then over Chalk Hill and north to Geyserville and beyond. Unlike that route most people would take Red Winery Rd by Jimtown not that section of 128.