The Red Rocks Amphitheater is an easy 40 minute drive west on Interstate 70 -- miniature Garden of the God's rock formations and historic stuff there. Then up to Idaho Springs on I-70 and back down through the canyons on Rt 6 to Golden to finish the day --
( Yorkshire, eh? Well, you'll be above 6,000' MSL and it's DRY there - don't let yourself get dehydrated!
)
-- with a "tour and taste" at the Coor's Brewing plant to finish the day.
If you have a whole day, you can make it up I-70 to US 40 to Berthoud Pass on the Continental Divide, thence up to the Rocky Mt Nat Park, back across the CD to Estes Park then down I-25 for a late dinner in Denver (about 9 hours with time for lunch and photos en route -- but the altitude will take its toll on ya).
H2