"Rajdhani" means capital in Hindi. So, Rajdhani Express connects Indian state capitals to the National Capital New Delhi. They will always originate from Delhi area. These are all fully air-conditioned trains enjoying the highest priority on the run. They can be trusted a lot more in case of punctuality than other trains. They halt only at important cities on the route.
On the other hand, "Duronto" is a Bengali word meaning quick. So, Duronto Express offers the fastest connection between any 2 cities between which it runs. They can originate from any city in the country and are not specific to Delhi region itself. These come in two versions-1 is fully air-conditioned and another is a mix of AC and non-AC...
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coaches. They come 2nd in the priority list. When first started, these were conceptualised as trains which will have only end to end passengers just like non-stop flights ,taking halts only for operational reasons like crew change, watering, food loading etc. But it was soon found out that they some of them were loss making due to their non-stop nature. So, now they are provided with commercial halts. So, in other words, a Duronto is a Rajdhani for connecting various parts of the country to each other. Hope this helps. Do contact if you have any further queries.....Regards...Ankur

Peter
It is really heartening to know about your forthcoming Indian trip. And the route which you have chosen i.e. Delhi to Goa is one of the best in the sense that upto Mumbai outsirts, you will witness long high speed runs & added advantage of beautiful scenery between Mumbai & Goa as the train will pass through one of the most challenging engineering marvels in the world i.e. the Konkan Railways. I've always wondered why don't Nat Geo or Discovery show a documentary of this route???
Now coming to the Rajdhani, I...
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feel what sets it apart from others is its speed & comfort levels. It's allowed to run at the maximum speed possible i.e. 130 kmph and till very recently it used to be the only train touching that mark along with the Shatabdi express which is a fast intercity express.
Its distinct livery sets it apart from others plus I was a frequent traveller long time back in the Delhi-Mumbai Rajdhani. I have always loved high speed trains & it's right up there with the best. Plus add to the fact that you are planning for 1 AC, I think there's no better way of exploring India than in the highest class on offer by a very prestigious train i.e. Rajdhani 1st AC. It's a different fact that its livery has been enroached upon heavily in the present day such that it might sometimes become difficult to spot it at 1 go. But nevertheless, the aura of certain things just doesn't diminish with time.
Regards...Ankur

Yes. If you select a lower berth, you are guaranteed a window seat, the only difference is you might get a trackside window which allows you to enjoy trains zooming in the opposite direction as well or a non-trackside window. But these are terms which interest only railfans.
And regarding your query about tables around a seat,then it depends on which seat you get. There are actually 2 types of lower berths on Indian Railways namely lower & side lower. The former will have a small table attached & you will be sharing that table with the person on the facing seat & the seat will be perpendicular to the window. But in the latter, your seat will only become...
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your table since it will be parallel to the window.