A dirt pull-off area on the south side of E. Lake Mead Blvd (NV 147) provides access to an overlook. The path is badly littered, the interpretative geology signs vandalized, and the smog makes for challenging photography, but maybe worth a stop if you're heading east early in the morning.

Las Vegas from Sunrise Mountain
White Rock Canyon, a moderate hike to the Colorado River south of Hoover Dam, is also the land access to Arizona Hot Springs.

Colorado River at the Mouth of White Rock Canyon
The mouth of Arizona Hot Springs canyon is a short but obscure hike southward along the Colorado River from the mouth of White Rock Canyon. (Boaters have a sandy beach right at the mouth of the Springs canyon.) The hike up canyon is also short, but more physically challenging. You'll get wetter, but warmer, as you proceed to the hot pools.

My list of places to visit on future LV trips:
In addition to Ash Meadows, other areas of interest in the Amargosa River area are Oasis Valley, Amargosa Canyon, and Shoshone/Tecopah
Muddy Mountains Wilderness Area
Buffington Pockets along the Bitter Springs Trail
Muddy River / Meadow Valley Wash
Mojave National Preserve's Piute Gorge.
Earthworks artist Michael Heizer reportedly has threatened to shoot anyone who tries to visit his monumental City uninvited, but this piece, near Nellis' infamous "Area 51", sounds like the must-see sculptural descendant of Tikal and other ancient American sites.
Please share your experiences in these places or suggest additional locations for Future Expeditions by commenting to this page.
The "Dunes" are more like badlands and the "Recreation Area" is a power toy playground.

Power Toy Tracks
Red Rock Canyon National Conservation Area is <1 hr. outside of Las Vegas. It features a scenic loop drive and hikes of various lengths and challenges.

View Coming Out of Icebox Canyon
Valley of Fire State Park is ~1 hr. outside of LV, with scenic drives and short hikes featuring unique scenery and native American petroglyphs. Popular Hollywood 'alien planet' landscape. Spectacular at sunrise/sunset.
Hoover Dam is worth a look if you're in that part of Lake Mead NRA. But be warned: the tourist traffic is heavy, the post-911 tour is minimal, and the declining lake doesn't produce the dynamic flow shown on the official site.

The River (Not So) Wild
The Nevada Test Site on Nellis Air Force base is a bizarre landscape of craters, ruins, and other artifacts from over 900 atomic bomb tests. Free day-long tours of the Nevada Test Site are given about eight times a year, departing from LV. Book early! No cameras allowed.