Just one more view on odor in coach. I work for a water dept and have had the same issue ODOR in coach, iron and manganese from a well with manganese.
The smell of sulfur can get into you water system, booster pump and tank. This is common when travel to different camp grounds and using the water or worse taking on water from the.water system. When checking in ask if the camp ground if manganese is in the water and do they treat for it as they are governed by DEP clean water act.. you don't notice till the water get warm from traveling or sitting for a day or two.
If you think a filter will work it will be expensive to buy a special filter. Bottom line is chlorine is good but breaks down and releases the manganese and the odor problem is back. The only way is to flush water tanks water lines and booster pump (as your booster pump stays idle when hooked up the a water system with pressure keeping booster off) and fill with treated clean water and add extra chlorine in the tank (keep a gallon of chlorine with you).
Bottom line check for MANGANESE. I have this problem in Salem Mass. and one other place in New Hampshire. It.s all ways good to flush your system often in the summer months. Happen to know if this resolves your problem.
Happy Travels
Dave P
2002 Country Coach owner
