Canyons are inherently risky. Flash floods occur without notice on sunny days. Technical skills & surrounding topography knowledge required yet does not eliminate risk.
Not the easy, but the fun...
The Mesa remains the most readily available hiking area adjacent to Alamogordo, yet it also remains relatively unknown due to the lack of trail information and the off and on status of the trail accesses over the years. Traditionally, Goat Springs trail was the trail of choice, and now may once again become just that as the USFS has re-established the trailhead, suggesting that the private property access issues may be cleared up... still, with the development of the foothills housing along that trail, it is nice to have options.
Marble Canyon provides exactly the same starting point, but instead of hiking up and into the houses, you head up a very nice canyon. Instead of city views, you take in the winding canyon walls and far, high vistas of the Mesa, along with the gurgling springs in the Narrows.
Leaving the mouth of the canyon, hike in past the old rock Quarry on your left, then turn right into the south branch of the canyon.
Once you've worked your way through the Narrows, and ascended the first stairstep rock strata fall, look to your right and up... you'll be about 1.5 miles into your hike and around 5200' in elevation when you come to the obvious sculpted sidewall drainage... and nicely centered high above you will see the Goat Springs trail cut slicing up through the cliff walls onto the Mesa. This is your point of departure from the canyon bottom.
From here you go roughly up and off trail. Choose your poison... the jumbled mess in the two drainages headed straight up... or the side slopes just above either of those. The easier choice is to probably follow the right hand cut, moving up and in/out with the right hand shoulder of the drainage... then angling further around to the right as you near a saddle that will appear to carry you away from the cliff cut. You can continue straight on up, but it is easier and nicer to angle up and to the right, slicing towards the Goat Springs trail at a lower intersection. If you crest the saddle, then do turn up and towards the cliffs... you will eventually cross the trail. Take it back to your right and on up and over the cliffs to the Mesa proper.
This route is not for those backpacking, or looking for an easy walk... but, if you seek a bit more adventure in your day hike, and some nicer scenery, this is a pleasant alternative route. I like to use this drainage down into Marble Canyon when I am returning from doing the Mesa Loop trail, just for the added effort and views.
...and, if those private property access issue come up again... this is the simple alternative!
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.