Hi Ticia, I can give you a review as these roads are regular rides for me.
First of all, there are no significant hills on the route. From the start in Newberg, there is a small climb up to north valley road and multiple 50-75 foot rollers once on North Valley. Enjoy the views to the south and the vineyards on your right. Be glad you don't have to climb Chehalem mountain as the Livestrong ride does....
As you head to Dayton, it flattens out but the views stay nice. South of Dayton is low traffic roads. There is less shade as you head back towards Carlton so have plenty of water if it is hot.
The leg on HWY 240 through Yamhill and towards Laughlin on the return is a high traffic no shoulder road. It's unfortunate the only east-west route in this area forces a lot of these rides (MS150 included) to use 240. I'd be vigilant anytime riding on 240. Once you hit the rollers of North Valley you are almost back and there will be a very nice descent back into Newburg.
Overall a nice route, just be aware of traffic on 240 ! Have fun!