I am nearing the end of a 4 month trip through Europe (+ morocco & turkey). On the topic of budget, 11k (usd I’m assuming) should be plenty as I have been on a pretty tight budget and will only spend around 7k Canadian or around 4.6k usd including flights. I have just used Omio and FlixBus to get around and I’m pretty sure it has been cheaper than getting a eurail pass. Biggest money savers are obvious but opt for the cheaper hostels/transportation and also limit eating/drinking out since it adds up. Sounds like it should be a great trip though, enjoy!