Hallo Andrew,
that would be awesome to have you here for a few month.
The Spring is coming soon and I hope we will be more outdoor-riders in the future.
We have an own thread for Outdoor-Activities: Outdoor-Termine Berlin
We will try to ride together every Wednesday, but it’s more street&trial in the City.
For Muni there are not so many possibilities in and around Berlin.
Last year we had a fun-ride at “Teufelsberg Downhill”. I dmaged my uni(and my foot) and leon did a spectacular flic-flac-dismount… 
This is an mtb-video: Ganze Folgen von ProSieben streamen in der Pro7 Mediathek auf Joyn
This Spring we want to check this trail: http://www.blitzmob.de/dhb/strecke_mueggels.html
We have no real Mountains here but this awesome trail is just 2or3 hours away:
http://www.racepark.de/
We rode there together in June, if I remeber correct.
So I’m pleased to ride with you here. 
Uli