The main benefit of this, other than fitness level in relation to riding, is they get to know each other better (while riding) and can race more effectively. The whole group can come together for general talks about things like nutrition and psychology.
Organization
If you are going the DIY route, make sure organization (or lack thereof) doesn't cripple the camp. Define routes, timetables, etc. Do everyone a favor and have a structured itinerary and schedule, and stick to it.
For example, don't come to a meeting place in the morning and ask the riders how much they want to ride that day and where they want to go. You are sure to get as many opinions as there are riders. When athletes come to camps, they usually just want to follow a lead and not have to think about things too much.
Add a Social Aspect to the Camp
For most teams, bike racing not only represents an athletic hobby, but also represents a social aspect of their busy lives. Training camps represent a small vacation away from everyday life, so make sure there is a good social component to the camp.
Perhaps organize a wine tasting or a trip to local sites of interest. Here in the Gold Country, we make sure everybody is aware of the impressive history of this area and try to present that to athletes.
Home or Away?
Clearly, getting away from home base can have its benefits, as it can eliminate any distractions from the riders and can be looked upon as a vacation. On the other hand, going away can cost more (especially in this economy) and may limit many members of the team from attending.
One option would also be to bring the organizer to the team. There are many teams that request AthletiCamps to come to them. It definitely represents a balanced approached to getting a camp done.
Schedule some down-time each day and plenty of time to rest up in the evening. Usually, the prime purpose of camps is training, and we tend to want to overload on the kilometers given time away from work and daily responsibilities. Allow for down-time in each day's schedule, and encourage the riders to get plenty of sleep each night.
For example, it may be difficult to schedule events after dinner. Riders are tired and had just had a nice meal together. Making them listen to a presentation may not be the best thing at that time.
There is no question that teams that train and race together with proper guidance have better results through the season. The more a team gets to know each other both on and off the bike, the better the chemistry will be when trying to achieve team goals (i.e. win bike races).
Use a team training camp to begin this process this year. And by all means, don't limit yourself to one camp. Think about multiple camps during the year, where team morale can be improved, a review of the season to that point can be talked about and goals for the rest of the year can be addressed.