Kedarnath temple is closed till march end. But Badrinath dham is open if you want to visit or you can go for a trek in kadarkantha. In rishikesh you can go for trek, river rafting, jungle safari, kayaking, camping, bunjee jumping, foxtrail etc.
there are no adventure activities in haridwar but you go for ghat aarti and rope way in mansa devi temple.