Kawaskai city isnt too far from tokyo. But it really depends on which part of tokyo you want to know how far it is from. We got the train from the west of tokyo one night and it took no longer than 30 minutes.
Which Airport are you asking about I gather Narita. From Narita its a bit of a hike possibly 2.5 hours give or take a little.
I havent explored Kawaskai a lot as Ive only been there to attend a rave. But the main street kinda looked a little like middle brighton but with a cobble stone street and cream colored buildings.