Andrea, a very good idea is to check what you are covered for away from home, home contents is what it is i.e. contents at home, you have to specify what you want if you want to be covered away from the home (and you pay a premium for that). For example we cover wedding rings, watches, cameras away from home under household insurance.
Looking at the Caravan policies, some cover you for bicycles, some do not. Surfboards, some cover, some do not. Best (and a must) is to get an alternative, get an quote to add these items on to your home contents policy, say you are taking specific valuable items away from home and find out what the excess is (and and additional premium), at least you know you are definitely covered. We have spent much time here talking about the unusual / unlikely event of someone breaking into our vans, but the reality is that it will be the kids bikes tucked under the rear bed-end that will go missing in the night. Point to be made is no-one really cares about loss of clothes, it is the dear (and loved) items we worry about, other than TV's your home insurer can cover almost if not everything, sums insured can be higher excesses lower, check it out for handing cash over. Think we might all find the caravan insurance offers very limited cover with big excesses. I say this after much research I find their general cover very disappointing.
We go to rivers, we go to beaches, many of the policies I have read exclude flood / tsunamis. Many of us are making a huge longterm investments buying a new van, we want insurance protection for all the events we have described in the above. But and the big but is primarily, seek out the best cover for the van..... then explore the options for the contents / bikes / surfboards. We are all here to talk about the vans, most important is the van.