All the owners' names need to be listed on the title to get license plates and tags for the trailer. If you use the word "or" to separate the names, any of the owners can sell the trailer without the permission of the others. Using "and" eliminates the possibility, since "and" legally designates the owners as joint tenants.
You must choose someone to insure the vehicle. While you can own the vehicle as a group, just one person or household can insure it, although you can divide the cost of insurance among all the owners. The group needs to decide on the insurance coverage and the deductibles, as well as the value of the individual family's contents while using the camping trailer, a consideration if a family brings along lots of electronic devices. The group also needs to decide whose responsibility it is to pay the deductible if one of the owners damages the camper while using it.
Scheduling the use of the camping trailer needs much consideration, as this could be the biggest source of conflicts. Deciding on a system so each family feels the usage is equal may take some discussion, especially for using the camper over holiday weekends and summer vacations. All camping trailers require maintenance and you need to address how you divide the maintenance costs. Someone who drives the trailer 30 miles for a weekend camping trip may not feel it fair to contribute to an equal cost of replacing the tires with others who drive it much further.
Consulting a lawyer to draw up a contract for the parties owning the camper could protect everyone's interest in the camping trailer. Establish the ground rules for using the trailer early on, so each owner knows what is acceptable and what is not. A checklist by category can provide the structure needed when sharing a camping trailer with other people. Taking photos of the camper before and after using it to document its condition may help resolve any disputes that arise regarding personal use of the camper.