You can measure the voltage in the rig with a volt meter or a kill-a-watt. If the volts do not drop too low, it is pretty safe to try. If the volts go too low, it can harm something.
I too have run AC successfully from a normal 20 amp house circuit and a very short, heavy duty extension cord for years on various 13,500 BUt air conditioners with no problem. But the voltage was good -114 volts and above measured at an outlet in the Rv with the AC compressor running.
You do need a quality 30 amp to 20 amp adapter rather than the typical junky 30-15 amp adapter.
Jim
