Thanks for your note.  

If you are still trying to decide about shore excursions, I was just 
remembering my trip and have the following observations:

I found the volcano on the Big Island to be marginally interesting, not 
particularly pretty, and from where I was staying (Kona), a very long day.

Kauai was very beautiful - the Na Pali coast is particularly spectacular 
(that coast and the nearby beaches are where South Pacific was filmed) but it 
is quite rugged and nearly inaccessible as I remember it except on foot or by 
boat.  I would highly recommend seeing it by boat if that option is 
available, otherwise, you can just drive up to the end of the road and get a 
pretty good view.  There is also a river boat trip I didn't get to take so I 
can't recommend it - it was popular with visitors.

I didn't make it to Maui but I've always thought it would be fun to go to the 
top of the mountain to watch the sunrise (in a car or bus) and then ride down 
the hill on a bicycle.  

There was a bay near Honolulu on Oahu (near Diamond Head) where I did my 
first-ever snorkeling.  It was very popular (crowded) but a lot of fun and 
while there were plenty of fish to see the reef itself was pretty dead (not a 
lot of pretty coral).

I found the web site for the dolphin lab where I worked but a quick look 
didn't indicate they have a visitors center.  You might call them when you 
are there if you have the extra time and want to go.  
http://dolphin-institute.org/

As far as your clothes are concerned, since you won't have to carry them 
yourselves, why not  take them all!

Have a great trip!

Love, Mark