Hi , 

I am planning to visit Istanbul ( not the whole Turkey) in the next summer July /augustus , with my girl friend ( we are  63 and 67 years old ) , the cheapest alternative  , Saturdays are preferred to start  and to come back  days to The the Netherlands ( Rotterdam or Den haag central stations) .Also I want to stay some hours  in some of the EU cities / stations  on my way to Istanbul ( not in the way back) and restart my travel again to Istanbul , the travel wil be less than 4 weeks including travel days .

-Is that possible ??  
Ofcourse :) 

-what will be the the costs  to go there and come back ? the cheapest alternatives , please , we are open for other suggestions over the travel days ...etc.  .
Depends on your traveldates and Route there is no precise answer as it really depends where and when you will stay. 

-what do we need for reservations , it is  now only ONE TRAVEL experiment, may be next year we will make it again , if it will be successful one . I do not think I will use the train for other destinations in the future .
You will need reservations for the Nighttrain.

-Please feel free to give us any other advice's.

Regards , 

Thanks ,

over this comment ,,

Depends on your travel dates and Route there is no precise answer as it really depends where and when you will stay. 

I have already asked over the cheapest possibility Yes it´s easy to ask for the cheapeast but there are other factors you have to consider aswell , 2 seats only (really 19hrs just in a seat? Vienna - Bucharest)  , and do you recommend any travel dates ??? because it is not easy to us to find these cheap dates . 

do we have to get an EU trein travel card / pas for the night train , what does it  cost the eu card or this reservations ? we are both NL nationality I personally would buy a Interrail Flexipass with 4days + cheap Point to Point tickets like Bucharest - Istanbul :)    

we do not need to stay any night in the way  Atleast you have to stay once somewhere on the Route (eastbound for example in Bucharest)… only few hours to vist that city , take som photos ...etc. and again in the following train … we will wat in that station … 

what is west bound ??? It´s easier to stop for few hours on the way Westbound compared to eastbound ;)

Can you give now approximate price ? Interrail 4days in a month + 3€ for a seat or 14€ for a bed in Cochette for Vienna - Bucharest + 35€ for Bucharest - Istanbul :) Return would be than 35€ again for Istanbul - Bucharest + Reservation 3€ or 14€ Bucharest - Budapest + 14€ for a seat or 34€ for a bed from Vienna back to Amsterdam.