You just plan a trip like this starting from tvm ponmudi via jadayu earth centre via thenmala via munnar via wagamon via athirappily like this they are close enough and you can plan a honeymoon trip with this Fort kochi is also a good place and all shops and tourist place will be open till 22 onam
You should definitely explore North Sikkim first as it remains one of the most underrated destinations on India . Some of the locations you shouldn't miss are :
> Tsomgo Lake
>Nathula Pass
>Lachung > Yumthang Valeey > Gurudongmar Lake If time permits you should also try to cover Pelling and Ravangla and few beautiful monasteries like the Rumtek . I think you should definitely think of a budget of 20-25k per person to explore this part as transportation is a main challenge there and tends to get a bit expensive . Hope this helps
You can try staying a night at the Taj hotel, lake Pichola. The hotel offers spectacular view of the lake and you won't feel anything less than a Royality