Firstly I'm taking two children to Disneyland, but want to go via Paris rather than directly there. I see the RER - A trains run to the Park, but the time taken to get there is stated as 1hr 5mins whereas I seem to have read it was only 35 mins? Does anyone know how long it would take from say Gare du Nord?

Secondly, I would be bringing them back to Paris from the Park around 9PM - are there any issues about safety I should be aware of when travelling at night to/in Paris?