Around the world in less than 80 days

I recall reading a novel length work 30+ years ago. It was loosely based on Around the World in Eighty Days I recall the Jules Verne story being mentioned in this work, but as fact not fiction. Something like "I realized I could beat the record of 80 days to get around the world".

A male character is traveling by balloon (or there is a balloon at the end, or both), some how gets most way around the world very quickly and lands on an island where a group of people have a futuristic society mostly based on good use of current technology. It may also have been that he was shipwrecked on the island and left in a balloon, traveling fast when the volcano erupts.

I recall one scene where the tables and chairs in the dinning hall, sink into the floor, leaving the table tops flush with the floor for quick easy clean up.

The island is a volcano and diamonds from the volcano play a part some how. I have Googled around for it, but I can't remember the title, author or how many days it took. There are a lot of hits related to "Around the world".