So you want to back up what? a 200gb drive to the cloud. What is the speed of your internet? And then there is the reoccurring monthly fees. And since you are on a RV forum, are you on the road when your computer goes down?
The fact is, the only way you loose your data is if the hard drive itself goes down. Mother board, memory, power supply, are some of the things that make a computer 'go down'. None of those affect a hard drive. As many others have said, use an external drive, about $100 will be all you need to spend and they last for years. Did you notice today that this system was down? What if that was your cloud system? Haven't you read that these cloud systems go down once in a while? Encrypt your important data and safe it on one of the free clouds.
MS, Google, Amazon, Apple, Dropbox are the usual favorites with Dropbox being the one that just about everything interfaces with. Each of these give you about 5GB more or less of storage.