If the demo deal is still working, you should be able to just download the TM2 titlepack from nadeo and play it as much as you want. Alternatively you could download other titlepacks that use the valley or stadium environment, such as ESL titlepack or TMplus and open the maps there.
The server can only be accessed from the TM2 TP.
So simply visit the ingame store and try to find out which TPs you can get. If there are some with valley and stadium among them, you can easily open regular stadium and valley maps in this titlepack. (In worst case you can use the editor of said Titlepacks)