I'm backpacking through Europe for a month this summer with my sister (for the first time). We purchased Eurail global passes. I know that for some trains you need reservations. My question is--how far in advance do we need to make those reservations? If we wait until we're actually in Europe, will there still be spaces on all of the trains, allowing us to make reservations at a station there? Or do spaces fill up and we should try and make our reservations asap? (We leave in 3 weeks).
Also, never having been to a train station before, how much time is "too little" to make a connection between trains?