Craft Art DIY countertops are pre-sanded and have an eased edge. That's what I went with, and I'm very happy. (Though my husband is handy, I didn't want to put one more thing on his honey-do list, so this project was my baby. I didn't think this was a good first router project for me, as I really didn't want to mess up!)

I don't have a wood countertop, but I think you are correct. I am confident you can just ease the edge to your liking with a sanding block.

My first choice would be a low-angle block plane maybe followed by light hand sanding, but if you don't have one of those use sandpaper backed by a block of wood or something hard. Don't use those foam sander thingies you find at the home improvement stores.

Get one with a pre eased edge and unless you have to make cuts on all 4 sides it will save you some time. That and give you something to compare your edge to so you can be more consistent.

But easing the edges is pretty easy. you just take a sanding block and go up and down and side to side at the same time.

Here is a link that might be useful: my (and fouramblues!) countertop is from here (Craft Art)