1- What scholars count as travelling differ, but I believe most agree that around 80 Kilometers is considered travelling.
2-Yes you have to make it up on a non-Ramadan day...
Its the other way around risa, fasting is obligatory for muslims, however since travelling could be hectic and tiresome, we have a permit to NOT fast. However its a choice up to us, its not like its forbidden to fast while travelling. Of course, we have to make up the day we didn't fast after Ramadhan.
1- Saying ' la Ilaha illa allah, Mohammed rasool allah'.. which means there is no god but allah, and Mohammed is his prophet.
2- Praying
3- giving Zakah.. Zakah is any sort of donation (e.g money or food)
4- fasting Ramadhan
5- Haj.. which is pilgrimage to Mecca (the Muslim's holyest City ).. (Only if you can do so)