An example of something that is not reserved for high lvl players, is the work to retake Stone. This is mainly player driven for now, but will probably get some DM involvement, at least when we get to the actual battle.
But already now, much work is being done, meetings are planned, supplies are being gathered, spies are sent in to spy, word is being spread. You can try to get involved in stuff like this too. There is a place for everyone to help in the war effort.