After 2 great weeks in Ireland last year, I'm going back for 10 days in May. I didn't spend any time in the Wicklow/Kildare area, so would like suggestions on what to see and do, over the course of 2-3 days.

A bit about me. I am 60 years old. I enjoy quaint/cute towns (Think Adare, Skibereen, and Dingle), don't mind touristy places, and pretty scenery, whether it's the ocean, rolling hills, or mountains. I am not a hiker. Historic ruins and things like that don't interest me. The National Stud, Glendalough, and Powerscourt all seem interesting, but I would like your input on those, and any other places you suggest.

This forum was invaluable to me in planning my last trip, and I'd be grateful for any help you can give me this time.

It might not be up there with Dingle and Adare but Enniskerry would be worth a visit, combined with Powerscourt Waterfall.
Glendalough is all about historic ruins I'm afraid, with the additional option of some hiking, which also doesn't appeal to you.
The National Stud is a pleasant place to investigate, particularly is you have any interest in trees/plants as there is a Japanese Garden on the same site.
The Wicklow Mountains lend themselves to a leisurely days drive; wander across the border into Kildare for a bite to eat in the Ballymore Inn in Ballymore Eustace.
If you are not too averse to walking, the towpath on the Grand Canal offers some opportunities around the tiny village of Hazelhatch. The nearby Lyons Estate is not open to the public (unless you pose as a potential purchaser to its estate agent.....) but there is a development nearby, the Village at Lyons Estate, where you can drop in for lunch.

If you are a Ballykissangel fan, you might visit Avoca where the series was filmed. It is in county Wicklow.

If you like houses and gardens, you could also see Altamont few kms S of Tullow (technically neither in Co. Wicklow nor Kildare, but Carlow is close enough to where you plan to go).
The famous Gardens are not really that huge, so it would be more a stroll than a hike to explore them (the trail down
Or find other objects of interest at carlowgardentrail.com

Kildare's Japanese Garden sure is a nice one (and a pretty old/historic one) - but if I remember correctly the entrance fee is a bit steep so it made good sense if you wanted to visit the Stud anyway and took the combo ticket.
When in or near Kildare, you can stop in Kildare "town" to see St. Brigid's Cathedral and the tall round tower (otherwise Kildare is not that grand compared with other county seats - unless you have also shopping on your list as the Outlet Village is right on the edge of town).

P.S. In para on Altamont, somehow one sentence got lost:
(the short trail down to the river can be a bit steep and slippery though)