Well you're supposed to get off the Interstate now and then and see the sites. If you read travel magazines or study geology you can get a better insight as to the best places to go. Even studying a detailed map will give you ideas of where to get off and what to do. AAA have some great travel guides.
In Sacramento, you should have gone East on Highway 50 to Placerville and from there up the road to Coloma where gold was discovered in California. On your way back you would stop in Sacramento, see the Capitol, the museums, old Sacramento and take a ride on a riverboat.
Our problem is that we're always hell bent for leather to get to or from Santa Maria, CA - Lincoln City, Oregon. Kind of goofy on our part, now that we're retired. I think we're still in the old "we only have a week for vacation" mode.
Kid just arrived back in the States today after three years on Okinawa. SIL will be stationed at MCRD-San Diego. Now that we're living on the Oregon Coast, looks like we'll be up and down the I-5 ribbon quite often.