The Ultimate:
Kayak the Napali Coast, Kauai, Hawaii. Nice to do this in two days, camping in Napali one night. Or longer. Afraid someone would steal the beached kayak though, during exploration of Na'Pali.
Hike into Na'Pali from Hanalei. camp one nite in Na'Pali.
Camno de Santiago de la Compostela Pilgrimmage. a/k/a The Way of St. James. Preferably starting in France, possibly at Paris, crossing the Pyrenees, on foot, though by bicycle would be acceptable to me, if not traditionalists. Months. This is the real ultimate.
Hiking in Northern India and Nepal. Better than paying $50k to a company for a chance of summiting Everest, imo.
Kayak along Baja in the Gulf of California. For example Puerto Penasco to Cabo. Or a shorter route.
Closer:
Cross Grand Canyon from South to North Rim and back.
Barranca del Cobre, Chih., Mexico. Hiking in the canyons. Train ride. (How's the gang activity there?)
Zion NP.
Gila NF. Snow Lake again, and somewhere else. See some elk.
Climb Picacho Peak, Az.
Hike length of Arivaipa Canyon, Az. Easy 2 day walk. Plan was to have someone bound for Phoenix to see a football game drop me off at one entrance, then pick me up at the other on the way back. Have to coordinate with Az authorities though, for permit.
In Phoenix: Squaw Peak, Camelback, South Mountains Park. Never made it up Camelback; walking shoes started slipping off on steep rock so I quit.
Not Far and Doable:
Quitaque Rails to Trails ride, about 64 miles one way.
Hikes in Caprock Canyons SP.
High point Guadalupe Peak, GMNP.
Hike in Bowl, GMNP.
Visit a small cave with restricted access, Carlsbad Caverns NP.
South Rim in one day, BBNP.
Drive the jeep trails near the river, BBNP.
Various short hikes I haven't done, BBNP.
See Sitting Bull Falls and Hidden Valley, off 137, N of GMNP.
Highpoint Wheeler Peak, NM.
Summit Sierra Blanca, near Ruidoso, NM.
Wichita Mtns Wildlife Reserve, Oklahoma. Hike some trails, see some animals.
Go up Quartz Mtn., N of Altus OK.