I grew up driving & riding that area. Sacramento sure has changed - what were once old two-lane country roads are now wide & smooth. The only import cars we saw back then were few and far between, except for VW bugs, and a few Triumph and MG sports cars. A friend did treat himself to a Jag XKE - but he was old, probably 30 or 35 or so...
The rest of us were in (see if I can remember 'em) Chevy SS's, Dodge Chargers & Challengers, Plymouth Roadrunners & Duster 340's, some Mach 1 Mustangs, a few GTO's and Firebird 400's... It was the day of the muscle car! Long time ago. The howl of open secondaries on big Holley and Carter 4v's, the smell of burning rubber... An occasional crunch when one of those over-powered/under-suspended beasts didn't quite make it through a turn... I-5 used to just dead-end south of Sacramento after a flat, wide run into the river delta area down near Courtland. With virtually no traffic, it was an awesome place for a high-speed straight line blast. I remember racing a red Ferrari 308 out there in my bright yellow '69 Chebby - had him until about 125 mph or so, then he pulled away slowly.
Another buddy got a Honda 750-4, I think he punched it out to 900+ cc's - it was a wicked fast early style cafe racer by the time he was done with it. I augmented my screaming yellow '69 Chev with a Suzuki GS750... Had a blast on those same roads you describe - the trip up and around Folsom Lake was good. Highway 49 was twisty and largely deserted.
Thanks for the memories - I wouldn't mind riding my Triumph on some of those roads again. Spring in the foothills was usually wonderful, green hills and wildflowers! Sacramento has changed - we rarely saw those beautiful, expensive imports back then in the late 1960's through the 1970's.
Regards, Guy