What is the make and model of your motorhome? Have you checked the condition of your starter battery..water levels, voltage and cranging power?
You may need to remove the battery and take it to a garage or auto parts store like NAPA where they can test it for you.
Of the battery is bulging, it shouold be replaced and be careful handling your battery. Use protective eyewaye, rubber gloves and heavy old clothes...no bare skin exposed in the event any of the corrosive sulphuric acid splashes.
The clicking when turning the key usually indicates a weak battery, which is clicking the solenoid, but does not have the power to turn the starter motor.
Give us more info on your RV, the age of the current battery and any info on the stste of the battery...if known.
Have you tried to boos it from another vehicle to start the motorhome?