I think your estimate is off by a factor of about 40. RDS is great at what it does, but it doesn't do that much. Getting the stuff RDS gives you for "free" might take a a few days to set up, but after that, your automated backups are going to take just as much of your time as the ones RDS gives you, ie, none.

If RDS saves you 30 minutes a week I'd be surprised.