cleaning toilet and tank (mold)

I winterized my Class C in April and have not used it since then so have not bothered to flush out the anti-freeze. Today I looked in the toilet and there was a film of black mold where the water normally is....yuck. Then I looked into the tank with a flashlight and it looks black and cruddy too. There is no smell. What is the best way to deal with this? I am taking a short trip in 2 weeks and wondered if filling the tank with water,adding a deoderizer/cleaner and some Dawn dish soap to it and then empty it when I get where I'm going might be ok. Or should I use bleach? I did spray some bleach cleaner (safe on plastics so it says) into the toilet already. Thanks!