I think it would be a great trip. monsoon will not bother you. in Andman temperature is average around the year same. in seven days, you can visit most of the places like port Blair city, Havelock and Neil Islands, north bay and Ross island, baratang jungle and mangroves, mount harriat. hotels are easily available at City or near airport. for convenience, book them advance. for hiring a car, you can ask the hotelier, they will manage. and believe me there is no extra cost charging for that. my Andman self arrange tour article is here if you want to visit. otherwise msg me I'll happy to help you.