need ideas for Denver/Boulder vacation with 1yo

We'll be arriving in Denver this weekend.  For 4 days I'm on my own downtown with LO while DH is in a conference.  We've been there before so I'm familiar with the 16th street Mall and the trolley.  One day we're going to the Children's Museum and one day the aquarium.  I'd love to go on the Mint tour but DS is quite a wiggler and I'm not sure I can hold onto him that long.  Any other ideas?  I won't have a car while we're downtown.

After those 4 days we're going to Boulder for a day and going around Denver but outside of downtown.  Any ideas there?  We found the Hammond Candy factory (DH is thrilled)- stuff like that would be great.  DS likes to be on the ground getting into stuff so sitting and watching something doesn't work very well.  We can drive wherever at that point.

TIA- looking forward to visiting again!