Day trips from Tokyo?

Hi!

I have booked to go to Japan early march, We are staying the whole of the trip in Tokyo for 8 Days. Currently in the process of sorting out some kind of itenary, but I dont want to go too overboard or it will just stress me out haha especially since this is also my first holiday abroad with my s/o 😅 Just looking for some reccomendations for any good areas for day trips from Tokyo, that are fairly easily accessible? e.g train only? We were looking at doing the area around Mt Fuji via an excursion express but I’m not too sure if it will be very visible around the time we are going.

Also, is it worth buying a rail pass beforehand, like one of those ones you can get unlimited travel for a certain area from? Or do those usually end up working out more expensive than just travelling with a suica card :)

Thanks!