There is a lot of good advice given here already. Utilizing council and district campouts is a good introduction for new scouts. However, the programs and activities tend to be somewhat repetitive. Parents tend to balk at expense due to the same events offered at each camp. Boys just want to be outside and never tire of BBs, archery, fishing, etc. and will always have a good time. It is important to promote the age specific camps (i.e. Tigers - family, Cubs family and resident camps, Webelos Webelos resident camp).
Now then, IMO there is nothing that can replace the well planned and ran pack family overnighter. It helps build pack cohesiveness (parents and scouts), provides leadership opportunities to Webelos, creates an excitement in the pack that can draw new scouts in and a host of other positives. So a few important things to consider:
1) Have an active and supportive pack committee
2) Get BALOO trained
3) Find council approved site
4) Allow plenty of time for planning
A simple list, but critical. If you do not have an active committee then it will be an uphill battle (doable but tough). They will provide the framework for the campout as explained through BALOO training. If some of them will go with you to get BALOO that will make it easier. Site choice is important as well. There are several BSA requirements that a site must have to be acceptable for cubs to camp there. All this stuff is given at BALOO.
As long as your committee helps, you get trained, implement that training, and allow enough time to plan all should go well. It did on our first Pack overnighter just 3 weeks ago!! Good Luck!!