The thing is that if you are landing a two stage rocket (or a rocket with enough delta-v for ascent) you can abort the landing back to orbit (unless you are crazy enouh to do direct ascent from earth without entering lunar orbit).
Apollo basically had a switch + sensor based tigers to start an automatic segvence that shuts down and drops the first stage, starts the seconds stage and flies it back to lunar orbit.
If you don't have an ascent stage or enough delta-v, you have to land, potentially many kilometers of course or even crash if something goes very wrong.
That's a very good point. A lander without an ascent module can't abort to space. Once you do your deorbit burn, you will land no matter what.
That's a good reason to have multiple supply/equipment depots on the surface before you even land the ascent vehicles. Walk up to the nearest one, then drive the rest of the way.
Also that's one good reason to have spare ascent craft (or supply depots) parked on low lunar orbit that could be directed to pick up any stranded astronauts.
A last option is a LESS-like lifeboat assembled from lander components. Surface to orbit on a convertible has some appeal.
A very simple "rocket chair" using residual fuel from the LEM. There were also variants for regular use during exploration using only leftover propellant from the descent stage.
Flown manually all the way to lunar orbit due to guidance computer being to heavy back then:
"Guidance in typical LESS designs was simple: an 'eight-ball' to show spacecraft attitude, a clock to show time since liftoff, and a planned pitch program. The Apollo Guidance Computer used as an autopilot for the CSM and LM had a mass of around a hundred pounds and consumed a significant amount of power, so computer controlled flight was out of the question. This would be one of the few cases where an astronaut flew a rocket manually all the way to orbit, and with far less instrumentation than normal."
Apollo basically had a switch + sensor based tigers to start an automatic segvence that shuts down and drops the first stage, starts the seconds stage and flies it back to lunar orbit.
If you don't have an ascent stage or enough delta-v, you have to land, potentially many kilometers of course or even crash if something goes very wrong.