Smell eventually goes away but I was wondering if I need to keep valves open or shut?

For one thing if the primary chemical fot the tank is chlorine then you have to keep in mind that it disipates with time alone regardless of content. Another thing is you should wash the tank out periodically to keep it clean. Using bleach and fresh water and a good drive down a windy road usually does the trick. Also any venting should be done to the outside of the unit.

Is this when the camper is in storage or in use? I the camper's not in use the trap seal in the toilet could have evaporated down allowing sewer gas to enter.

I was wondering if I need to keep valves open or shut? If you're asking if you should keep the water shut off valve open and the camper pressured the answer is No. How long do you store the camper at a time? Back to you, Tom

Is this when the camper is in storage or in use? I the camper's not in use the trap seal in the toilet could have evaporated down allowing sewer gas to enter.,
If you're asking if you should keep the water shut off valve open and the camper pressured the answer is No. How long do you store the camper at a time? Back to you, Tom

The camper is set up permanet and the sewage valve is what I was questioning,open or shut. We go every weekend.

Does the smell come from the tank or the bowl? Is the sewer shut off put there by the park so that if the campers moved the line can be capped off or did you install it yourself?
With a perminate installation I'd keep the sewer line open unless them park's subject to backups.
As for the smelly toilet it could be a faulty wax seal. Could the smell come from inside a wall? Is it worse at night? Back to you, Tom

Does the smell come from the tank or the bowl? Is the sewer shut off put there by the park so tyhat if the campers moved the line can be capped off or did you install it yourself?
With a perminate installation I'd keep the sewer line open unless them park's subject to backups.
As for the smelly toilet it could be a faulty wax seal. Could the smell come from inside a wall? Is it worse at night? Back to you, Tom

The sewage line runs from the camper directly to the parks sewage system. The smell is from the bowl. I've been told to close the valve ( just push the handle in under the camper ) and then before I leave open it, run some water, let drain and close back.?

This is a valve that cuts off the sewage flow from the camper to the parks sewer? Is the smell worse in the bowl or at the base? Your toilet has a trap seal in it designed to prevent sewer gas from entering your unit. If the bowl level was too low that would explain it. Has the bowl level been low lately?
Any moisture around the base? Let me know, Tom

This is a valve that cuts off the sewage flow from the camper to the parks sewer? Is the smell worse in the bowl or at the base? Your toilet has a trap seal in it designed to prevent sewer gas from entering your unit. If the bowl level was too low that would explain it. Has the bowl level been low lately?
Any moisture around the base? Let me know, Tom

I'm not sure but I don't believe so. I'm going to the beach Thursday and I'll stop and check and let you know. Thanks.