I'd concentrate on one area, we just spent over two weeks with a week at Cortez CO and the second week at Monticello for Arches and the east side of Canyonlands. From Cortez we did Mesa Verde, Hovenweep, Canyon of the Ancients, Monument Vally, Valley of the Gods, Moki Dugway and some other areas. And we didn't feel as tho we saw everything that we wanted to.
And a couple of years ago we spent over a week at Torrey for Capital Reef and didn't see everything there. But we go on the 4WD roads, if you do not then there won't be as much to see.
We used Monticello because it's higher and cooler and less congested that Moab. But in April the temp won't be as important.
But a week in Torrey and another in Moab will give you a good look at both areas.