What a great location! The area Castello/ Arsenale gives you a sense of living in Venice because it's not too touristic in this area. But still it's very close to San Marco square and other main sights.
April is a great month to visit since the weather is already very nice and it's not too busy. We loved going around all different areas of town, walking or by Vaporette and just drinking our coffee or spritz in the morning on the square at Arsenale.
Thanks for the tips Fabrizio!