Maytrix -
Precisely the issue. So Cooper Island is okay with me getting and paying for a ball in the morning, and then leaving the dinghy on the ball for the 2-3 hours we would be over at Salt just after lunch? If so, then there is no reason to dinghy over.
Others -
And, there is certainly the outboard failure issue. My most memorable was in 2007 in the Tobago Cays. No way to row against the current, and I was headed out to sea. Fortunately, my then 25 year old son on the beach was able to persuade Claudia, a very attractive and tanned all over young woman off a very large French yacht, to come rescue me, leaving her boyfriend Franc on the beach with my wife and daughter-in-law.
As they got closer, I could see that my son didn't know quite where to aim his eyes so that I would not see him looking at what was coming at me (if you get my drift)! I learned later that back on the beach, Franc was pragmatic: "I've traded one for two!"
Recalling that story is good for family laugh at least once a year.
Thanks for the advice. Big boat it is.