Hi Gordon - welcome to the forum!
As you have probably already discovered, you have a few options.
With a Bareboat Charter, you will have the boat to yourselves and be able to get around as you like - that's got to be appealing. Technically, you don't "need" experience for a bareboat charter and as you already have some it is a possibility to consider. It just depends on how confident you are with your abilities.
With the Whitsunday tour boats, the trick is finding one more family orientated - especially if you are doing a multiple-day tour and sleeping onboard. As a general rule, the more expensive the package the less young backpackers are likely to be aboard. Of course, this is no guarantee of how your fellow passengers will behave.
Chartering a boat with a crew is another option, but obviously a much more expensive one...
A good compromise may be to choose the bareboat charter, but take a skipper with you for the first day to refresh your skills - some companies offer this option.
Have a look at some of the local businesses to give yourself a better idea of what is available and the pricing:
http://whitsundayssailingadventures.com.au/,
http://www.whitsundayescape.com/ and
http://www.sailing-whitsundays.com/ are a good start.
Hope this helps!