I am Indian -- grew up in India, and am currently visiting my family in India. I do agree with what others have said: Indian mainland can get pretty hot in April -- expect temperatures to reach ~40C(104F) or so. It shouldn't be that much of a problem if you are well-hydrated etc -- I think the tips others have to offer as visitors are more useful than anything I can say from my experience growing up here.

I have no experience with tour planners, but I have been told that some small non-reputed tour planners do take non- Indians for a ride (figuratively) when planning trips for them. Its best to get your tour plans and rates audited by anyone who has lived in India or has a long experience in India.

If you need tips on places to visit etc, feel free to let me know and I will try to plug in something.

Slightly off topic, to Ursula: Its very nice to know that you are friends with Margaret Deefholts! I haven't read any of her work, but one of my Indian friends who grew up a strongly Anglo-Indian part of Kolkata (India) has, and she really likes her writings -- to her, it reminds a lot of her Anglo Indian friends. Commend her on my part when you do meet her for lunch!

Arvind