+1 for the daytrip. If spending two days you could spend one day mostly walking the footpaths in the hills around Kamakura, which is a great way to spend a day. But on a short trip might not be the top priority.

If you treat it as a day trip, you should be unencumbered by luggage - so get off the train at Kita Kamakura, see Engakuji and then walk down towards the Hachimangu shrine and "downtown" Kamakura.

You should see some flowers (there's more to Japanese gardens than cherry blossoms)
http://www.kamakuratoday.com/e/sight.../f_spring.html