All destination mm.. i think the distance could be the task because so many places arr there to see but may be a week or 10 days will be good if you have your own vehicle
Depends on which part you want to see and what. Kumaon side of Uttarakhand and garwhal side both have alot to offer.depends what you want to see. if you want to trek or just do a comfort travel. but a minimum of 10days.