The Interrail Pass offers a great amount of freedom and choice to explore Europe however you want. You can simply hop on and off trains as you please (but do bear in mind the need for additional reservation supplements on certain high-speed and overnight trains), and if you decide to stay in one place longer than you anticipated then you're totally free to do so!
Please note that you just must fill in the details of each journey before you board the train, bus or ferry you travel on.
Other Interrail Pass benefits include discounts on certain ferries, entitlement to Pass-holder fares on the Eurostar services to/from the UK, and discounts in some European hotels and hostels, museums, festivals and other local transportation.