/dev/null,
How far can you travel from town? I have several suggestions, some close, some far.

Very Close:
Jefferson County Open Spaces That's the county you will be staying in.

Sorta close:
Golden Gate Canyon State Park
Brainard Lake Recreation area

Close but could be more than a day trip:
Rocky Mountain National Park

Any of those should keep you plenty busy. Have fun and I hope you enjoy your stay in Colorado.

D.