Rajasthan's brilliant. It's much less populous than the plains, and I found the cycling really easy (I was in India for about six months a couple of years ago).
Roads can be a bit hairy, especially at night (I tried not to ride at night, but events get in the way). I did get knocked off my bike by a motorbike - the rider and his two mates (every motorbike in India has at least three people on it) were riding too close behind me and too busy grinning at me to pay attention, so when I braked for a pothole, they clipped my pannier and chucked me off into the dust. That was on the road from Chittorgarh to Bundi. No damage to me but I had to clip my pannier back on with cable ties.
On the roads, just go with the chaos. If you go to Jaipur that gives you a good sense of what it's like. It's much quieter as you get out into the desert.
Probably worth taking some chlorine tablets in case you have to fill up with water from a pump or something. Bottled water is fine, and widely available - and you'll need plenty of it if you're going into the desert, even in the winter.
Food wise, there are loads of street vendors and roadside dhabas. It's easy, and good, and cheap. There's a huge mark-up in tourist areas, so follow the locals if you're concerned about budget. I never became ill from the food (only the water), so I wouldn't have too many concerns about that. Don't eat things like salads and apples unless you rinse them using filtered water. Bananas are widely available as on-the-go food.
The hardest thing to deal with (probably less of an issue if you're only there for a week) is the constant attention. Most of it's friendly, but it's wearing after a while. The noise can be overwhelming as well. Consider taking an Airzound with you so you can compete on equal terms. The poverty is striking as well, and there's a harsh contrast between rich and poor (go to Connaught Place in Delhi and look at the glittering Apple store, compared to the skinny rickshaw drivers kipping under their machines). Everyone will treat you as a rich foreigner, which is fair enough, as you are, by comparison. Beware of scams, but they're mostly pretty obvious (always agree a price in advance, for example).
And India's just different. Body language is very different, and be prepared for complete misunderstandings even when you're all speaking in English. Hotels are hilarious, they're all like variations on Fawlty Towers. Me and a mate were the only guests in a hotel where the staff were charming and looked after us really well, and we had a cracking meal, but they seated us under the renovation works, and carried on drilling and hammering while we were eating.
Just go with the flow. Here're my Rajasthan photos:
http://www.flickr.com/photos/30024450@N04/sets/72157629256768395/
