I can tell you from experience folding out camp cots are not comfortable at all. They are like sleeping on the floor with less room. I suggest an aerobed for sure i have experienced the air loss in the middle of the night also but this can be from the plastic stretching and until it is completely broken in it will continue to do this. Make sure your air intake is sealed off as best you can. I have slept on a aerobed for 3 nights without pumping it back up. They are the best choice for your money and a lot more comfortable.
+1 with Chuck & Gail...ThermaRest self-inflating sleeping pads come in very comfortable thicknesses, LAST A LIFETIME, don't leak, travel compactly, don't require pumps or repair kits, have lifetime guarantees, and most importantly...don't present the "heat sink" effect that invites lousy sleep or hypothermia due to hollow air pockets inside or empty air space underneath inflatable air mattresses or cots. Cots, hammocks, air mattresses are great in their place: summer camping, heated enclosures, or used with electric blankets.
Bought my Thermarest mattresses in 1973. Best investment in camping equipment I ever made. Camp mostly in a 5r today but the Thermarest pads are always brought along for extra guests to sleep on floor.
1994 27sl Alpenlite with many mods, 2001 Dodge Cummins 2x4 3.54 Auto trans built shift kit and 2nd gear lock up mod. Mojave Green billet, triple disc low stall torque converter. Gauges and raptor 3/8inch fuel system. 12.5 mpg avg
Blantex makes a steel frame, foldable cot with a fairly comfortable looking mattress. The description claims it's of the same standard as the roll away cots they provide you with in some hotels. It's pricey though at $185. Here's the link.
I think a lot of it depends on her level of fitness and her size. My own mom is in good shape for her age and is of average size. So, using her as a baseline, and that I own a pickup truck, I would go with something like this: If that's not an option then a standard camping cot with a foam pad would work.
A few 5 dollar pillows in a sleeping bag as a "matters" goes a long way. Make sure to clear the ground of rocks and sticks before laying out the tent (of course). No matter what you put down to lay on won't help an old back get off the ground in the morning though. walmart has some killer cots with springs surrounding the canvas and they include a thin matters pad. She'll love you for it. think they're around $40 in the camping isle!
Any day camping beats the best day on the ranch until one day of camping ends up costing over $5000. Been there, done that, watch out for low branches!
A Campers Three Best Friends ~ CampingWorld | 12Volt-Travel | Walmart