Kerala is one of best place ,it has many tourist places Shikara rides in Alleppey,Enjoy watching elephants bathe in Kodanad, Watch snake boat race in Alappuzha,Enjoy your stay in a treehouse in Wayanad
,Go for a spice tour in Thekkady,Explore the coffee plantation fields in Wayanad
, Watch the Theyyam performance in Kochi,enjoy paragliding , tent camping , trekking in vagamon, temple city thiruvanandhapuram ,taste authentic malabar cuisine at kozhikodu, monroe island, lakshadeep island, varakala beach, thissur pooram festival at Krishna temple and many
You should start with Delhi to meghalaya ( full of beautiful mountain and best waterfall in India) then goa (beachs and night life) then Kerala ( house boat and beautiful nature) then manali- kasol( mountain and camping and tracking and adventure) Rajasthan ( desert and get chance to see Royal side of ancient India) I think that's all for your this trip🙏
Beaches n hill station r normal nowadays but if u r in India thn explore Indian culture and Indian history...
Rajasthan is best explore Rajputana tradition, their history, Rajwade n forts.