Wayanad ( Kerala), Connor, & Kodaikanal is good for summer trips in South of India. Even Chikmagalur tea estate and hills near Chikmagalur is lovely to spend one or two nights... the day time in all these hills stations will be hot however the nights will be pleasant and u will like it. If at all u plan Site seeing then start at 5:30 am. And end it by 8:30 am. Good Luck
Happy Travelling!!!
Pondicherry would be a good choice for a beach vacay. Munnar, Coorg and Ooty and some hill stations you could check out. Also, if it's a long trip, you could try touring Kerala.