Unfortunately you need a separate ticket for the trip to/from Venlo. There is a pdf-document (only in German) that lists all trains that you can use with the Day ticket for Germany (Quer-durch-Land-Ticket) - there are some train lines in Austria, Switzerland and Poland, but none in the Netherlands.
Another option could be to use the Weekend ticket for Germany (Schönes-Wochenende-Ticket) which includes the train line Kaldenkirchen – Venlo adn also the bus line 929 Niederdorf – Venlo. Here is the source (also only in German)