The trend that i have observed is - there is a better chance of getting tickets from Mumbai to Surat than say getting tickets from HYB/SC to Surat in a long distance train.Actually,i guess that applies to almost all the routes.The shorter your journey is,the better are your chances of getting a ticket even if the date of journey is close by but yeah....still,you gotta keep an eye on the 'ticket availability' for that certain date.Mumbai - Ahmedabad offers a bucketload of connections.........from Shatabdi to Garib Rath to Karnavati like Intercity Express to various Superfasts.So,whenever you get to know your D.o.J,just look for availability in 17037 and if there are no tickets available then do check 12220 SC - LTT Duranto.Personally why i insist on 12220 is,tickets might run out in a train like Hussainsagar faster than in a Duranto.Duranto tends to offer you a few extra days especially when you...
more... are not sure of your journey date.When i went to meet my brother who lives in Ahmedabad i got tickets in 12220 and i kept checking on it's tickets availability and there were fair few tickets available even 4 to 5 days prior but i guess as BG said,October is a month of festivities so may be we can add a few more days so that we don't leave it too late and from Mumbai,i opted for Bandra - Delhi Garib Rath and got down @ ADI.If in doubt just drop by here with a query and am sure people in here will help you out but i hope you get the tickets as per your convenience. :)