There are lots of personal trainers (employed) and lots of personal-trainers-in-waiting, not as many waiting tables since so many of those serving jobs have been lost lately. Finding a job -- any job -- is much harder than it would have been a year ago. The daily paper now runs maybe a column or two of "help wanted" ads, whereas a year ago there would've been two pages at this time of year.
I live on Maui. There are several gyms here: Gold's, 24-Hour Fitness, and a few "independents." The local gyms seem to have a fair amount of turnover, or they used to advertise a lot. (Not now.) I don't know if people got "placeholder" jobs there until they found other work, or if the jobs just didn't pay enough.
Most of the nicer hotels have a gym or some kind of workout facility, and also offer a selection of classes in weights, aerobics, water-fitness, yoga, etc. Many of these operations have been contracted out, either to a fitness management company or via subcontracts to companies who offer each specialty. In other words, very few of the hotels hire fitness people directly, but you could contact the people to whom they contract the work.
From a casual, personal observation standpoint, I can tell you that the gym business seems to be in a bit of a decline -- facilities not being kept as nicely as they could be, equipment not being replaced, and lots of membership "specials." (I know it's that time of year, though, so that could be a factor.) I walk in the Kaanapali resort area almost every day, too, and note the activities at the various resorts there. The Sheraton just opened a new spa last month, the Westin's gym seems fairly busy, the Marriott has a yoga/water fitness franchise that seems very popular, and the Hyatt's fitness center is up-and-down. That's just one area, though.
Another thing I've noticed is that the beach park nearest my house used to attract a number of (what I presume are) freelance personal trainers and "life coaches." I know the latter isn't fitness, exactly, so maybe the guy was just there to swim, but these guys are all gone. I was never sure whether their operation in the park was legal; I think they were supposed to have a permit. So they could've just been flushed out by park security, but there's a lot less of that kind of "activity" in general.
I hate to discourage people from moving, but the economy is so tenuous that it's hard right now to encourage anyone to move who doesn't have a high-demand skill or trade. There are many fewer tourists (today's Honolulu Advertiser says hotel occupancy is as low as it was just after 9/11:
Hotel occupancy in Hawaii drops to 60.9% | HonoluluAdvertiser.com | The Honolulu Advertiser) and locals are scrambling to take whatever work can be found and not really spending anything extra because nobody really sees an end in sight.
Good luck.