Every part of Himachal is beautiful.I have been to Shimla Manali and Dalhousie and all of them were beautiful.you can visit shimla in 3 nights 4 days very comfortably(covering shimla local sight seeing,Chail palace,Kufri,jakhu temple,kamna devi temple,Himalayan zoo,Naldehra)
I visited Manali for 1 night two days where on the first day I visited the local sight seeing(mall road,monastery,Hidimba temple,Vashist Ashram,Siyali mahadev,Manu temple) and on the day I visited solang valley.
Dalhousie was also a short weekend trip where I experienced Paragliding,Zip lining and a visit to Khajjiar...
Himachal is epic. There are just too many great places depending on your choices. Regular Hill Stations 1. Manali
4. Mc cleod ganj Offbeat Hill Stations 1. Palampur
2. Dharamkot Paragliding Destination 1. Bir
2. Khajjiar Snow Destination 1. Rohtang Epic Road Trips 1. Spiti
2. Sangla 3. Narkanda
4. Chitkul Beautiful Treks 1. Parashar Lake
2. Triund Trek Tough Treks 1. Rupin Pass
2. Chitkul to Yamunotri.
Hey buddy, I have started creating Himachal series(playlist) on my YouTube channel...you can visity my channel and it may help you with some beautiful destination details with budget (like Mcleodgunj Video). And please do SUBSCribe if you like my videos. Happy Journey...cheers! https://www.youtube.com/channel/UCNXH7j0ZsC-SxaWyAlgMeag
Depend on you if ur visit with friends trip is about 20 days.. cover shimla manali 2~2 days each and going ladakh with bikes from manali its true adventure but it ia possible only june to september rest of the year only trip is 7 to 8 days manali and shimla rohtaang pass or gulaba pass solang valley going with family 7 to 8 days trip is more than sufficent
or if ur going mclodganj dalhousie extra 4 days inculded in your trip but i suggest if u plan shimla manali plan different and dharamshala dalhousie plan different trip