I had a horrible experience as a full timer. I thought I had insurance appropriate for a full time RVer. I even went to an independent agent who specialized in setting up insurance for full time RVers. He was recommended and worked with my mail service provider in South Dakota.
When we had a major theft we found out the coverage was not sufficient. In most cases, people have homeowners insurance which provides coverage so coverage for RV insurance would be a duplicate service with duplicate costs. Of course, that is not true for RV insurance. After the loss I tried to find appropriate coverage. I eventually found a policy that worked but it took a long time and was very frustrating because most agents just don't understand and most insurance companies just want you to use their services even when they are insufficient.
Sure you might also need a rider for expensive items such as musical instruments or cameras. That is in addition to the issue that most RV insurance policies are very limited in theft or damage coverage for personal property aside from the RV.
If you are a full timer, check the fine print. You are likely to find that your policy provides little or no coverage except for the RV itself.