How much would you spend on a six-month trip

How much would cover a six month trip? Would 3000 US cover mid range hotels/guest houses, train travel and flights . I think it should.

You might like to have a look at this poll It will give you an idea of what members have been spending over quite a wide range. You don't say whether you are including your flight to and from India in this. If you are then it would be a pretty tight budget. If not, then it's an amount which quite a few members have managed on.

If you want my personal advice it would be useful to have an extra amount of cash in reserve for those times when you would like to book into a better hotel, eat in a more upmarket restaurant, or visit some historical sites or national parks.

You are not clear on the following :
Will you spend long times in 1 place ?
Say you're always just spending 3 days at all the places you visit, or maybe you'll spend 2 months in a place in goa, and 1 month in Manali ?
Long stays will have a big impact on guesthouse-prices & you' ll learn to know the shops/restaurants that or offering good value for money.

I would spend 2-3 months in the Himalayas and work my way down south. I will mostly avoid big cities as I've already been to them and didn't care for any. This does not include flights to and from.