Traveling to Japan in May with my wife and 6 months old baby and looking for a nature getaway in between visiting Tokyo and Kyoto.

First I thought of Hakone, but I am not sure it is the best experience. I am also thinking of Shuzenji Onsen or even Kamakura.

Not looking for Onsen specifically but it would be a plus. Same thing about seeing Fuji. We really want somewhere to relax in nature (2-3 days) in between Tokyo and Kyoto.

Any recommendations?