So a couple of days, see some sites from the car & a couple of hikes? So much to see, so little time.
Just yourself? How fit, how many hikes can you do in a day? I'm in agreement with the general sentiment that more "must sees" are in the High peaks, here are a view from the South of the Route 73 area though:
There is a good view you can see from the car in Newcomb of the High Peaks. The view from Elk Lake Lodge is fantastic also (open this summer?) You can easily walk up the road from the Dix parking of Elk Pass & the peaks overlooking Elk Lake is fantastic. It's graced their ad for years.
In that general area, Vanderwhacker provides a great view of the High peaks from it's summit
For the Keene Valley, ADK Loj area....
Stop at Chapel Pond for a couple of minutes.
There are two general views on Gothics, the views are great from it except you can't see Gothics, maybe the best visual peak in the ADK's. (The Pyramid option addresses that to some degree)
If I'm in the type of shape I was in at age 30 or in 2006, if it's rained lately, I hike in to Beaver Meadow Falls seeing the Ausable Club - maybe even going to the 1st lake. (A trail runner could probably runmost of this) The lake & fall are wonderful. I then drive to the Garden & do the Big Slide & Brothers loop as the views are great & you're across the valley from Gothics. Whether you do the Gothics hike or this one, you really can't go wrong. I'd say the footing is a bit easier on the Big Slide trip (although maybe a decade plus is dulling my memory)
I do a little shopping at the Mountaineer, maybe a slice of pie from the Noonmark & then head to ADK Loj. Even after a full day, you can climb Mt. Jo, it's about 700 feet above the parking lot. The view from the Loj road is fantastic too, even if you don't do Jo.
On the second day, I'd do the Wrights Algonquin loop (Throw Iroquois in too) & then descend to the lake & head out through Avalanche Pass. If you get an early enough start, you should have enough time to drive up Whiteface & take the Elevator up to the top. Can walk back to your car. This will bring you past the Olympic ski jumps too.
Hurricane is a Great peak & Cascade is maybe the easiest 4K peak in the East. If the summits are socked in & weather is miserable, Ausable Chasm is neat as far as a tourist roadside attraction goes.
I'm heading up myself in a couple of weeks, staying in the central region but just thinking about the ADK's is a plus.