great hike and a fun drive to get there (about 20 miles). But if I remember correctly, there is a steel ladder you will need to climb up and down on the hike. Not sure how that will work with a 3yr old unless he or she is in a carrier.

I'm in the minority here, but I'm not a big fan of a Delicate Arch hike. It's somewhat long, no shade, and it's not that scenic until you get to the arch. Personally, I'd just do the shorter viewpoint hike and spend my time doing the Windows hike and Devil's Garden.

And I agree with Sandstone Cougar--Devil's Garden is worth it even if you don't do the full loop. There are several spur trails to interesting arches and features so you can sort of customize how long you want to hike. Best hike in the park. If you do go further, make sure to keep tabs the toddler, as the segment of the hike on the fin has some exposure. My young nieces and nephews have hiked it many times without incident, but it's still something to watch for.

One of the best hikes in the park is the Fiery Furnance, but they don't allow anyone under 5. And you either need to go on a ranger-guided hike or get a permit (not recommended if you have never done the hike as there isn't really a trail or markers).