We were on the Xpedition 3 yrs ago with our son who was 17. Had a great time, but food is not near up to Regent standards. By all means, avoid the hamburgers--they were awful. Salads and fish were good and safe bets. The ceviche is not raw, so I even ate some, and it was very good.
Room is pretty small--I had to sleep in the bunk because our son is 6"4' and wouldn't fit. Very compact but functional bathroom.
There are usually 2 landings per day with choice between easy and more difficult. We always did the more difficult option, and they were really easy except for the fact that a lot of time you are walking on lava that has solidified. Be sure and bring hiking shoes that can handle that. Sandals will not work on the lava.