OK, got back from Europe, sorted it out.
Hope this can help a traveller on this Earth.
My 52 days long trip cost me 2975.81€ precisely. As of today's exchange rate (Nov. 5), it's 4491 $CAN, or 3869 $US.
This includes everything (hostels, meals, water, train tickets, beer, souvenirs, tram / metro / bus tickets in every town, bike location, etc.) except for the plane ticket and the insurance I took before leaving.
I spent 44 days in hostels, 8 days on CouchSurfing and such (includind the Paris apartment). I didn't go much to museums and such though (went to the Louvre on a free entrance Sunday), and rarely paid more than 15-20€ a day for meals, which I would frequently prepare myself, or buy on the run.
I didn't have any train pass of any kind before leaving ; as a way to preserve some improvisation, I bought everything on the spot, therefore I never benefitted from a reduction (such as early reservation tickets) for all the trip. And so I went through eight European countries (France, Belgium, Germany, Italy, Austria, Liechtenstein, Switzerland, Monaco), and even took a return flight Karlsruhe-Baden (Gmy) to Roma (It) on one occasion, for the sum of 852.50€. That's 18 train trips and one flight, full price (unfortunately, I'm older that 26).
So I spent an average of 57.23€ per day (86.38 $CAN). I never refrained my sometimes abundant alcohol consumption, went to all the places I wanted to go before leaving (and when I didn't, it's because I lacked time), ate and slept quite well, and had the time of my life.
Ladies and gentlemen, I rest my case...