If you could utilize a dehumidifier in your regular house, I would buy a nice sized one with a continuous-drain feature to temporarily benefit the motor home. Or maybe get a little unit exclusively for the motor home. It really is most effective in drawing out humidity behind walls an such.
My brother owns a short 22 foot Starflyte and keeps a continuous-drain humidifier in his outside stored rig because it prevents respiratory issues for his wife's asthma.
This is why I advise to dry out a motor home with a dehumidifier. It truly dries up the rig, inside and within the walls, avoiding any such respiratory concern.