Anyone have any recommendations for anywhere to stay as well as cheapest forms of travel from place to place? Also recommendations for places to go. I am a 21 year old female, I will be traveling with 3 friends and we are just trying to make the best out of this trip! Any advice/recommendations are appreciated. Thanks!!
Definitely look into Megabus for cheap travel but make sure you get your tickets in advance to get the best prices. Also check out Meininger hostel in London and Amsterdam – they're mostly in Germany but a great group of hostels.
Megabus is quite cheap. A lot of the cities on your list are also serviced by bus about so you may want to look into bus passes that are offered by them, eurolines, ecolines, etc. As you're under 25, I'd also suggest looking into inter rail/ eurail passes, although busses are generally cheaper.
How much time do you have? You have some pretty big jumps between major cities - it might be worth checking budget flights for those, or overnight connections. Or, if you have the time, stopping in between and seeing some smaller places.