The railroad Pass will work to your favour provided you do a few things based on the itinerary you provided, pretty simple really and with a full month at your disposal, it can easily be done...I could.
First, You would have to consider taking a couple of long night trains, at least. say from Amsterdam-Berlin, Paris-Berlin, Paris-Vienna with a change of train in Munich, Paris-Brussels r/t as a day trip, or Munich to Paris. Secondly, on this night train, preferably a CNL, forego the sleeper or couchette. The extra money you'll need to pay is for the reservation of a seat in a 6 passenger compartment where you can sleep upright. (On a Frankfurt-Vienna night train, an EC, 2nd class compartment seat, I paid 19 Euro in May). By day from Vienna-Berlin, as long you don't take the route going through the Cz Rep., ie. only through Austria and Germany, your Pass is enough...you won't need to pay extra for a reservation...I didn't last summer and neither this time in May.
Save the short trips for the point to point tickets. Take ICE or IC trains if you have a choice. Avoid taking the Thalys trains, even if you have to lose a hour or two. Whether you arrive in a city at 1500 or 1700, it's not a big deal especially in the summer, which is the time I always travel in Europe.
Your itinerary includes going through some very lovely countryside, Paris to Munich to Salzburg, the North German Plain, Munich to Vienna. I envy your one month over there with that great itinerary.