It's annoying that our side has to respond to ridiculous attacks like this one, but I'd like to put in my two cents this time.
I was born in 1979 and have almost always lived in a lower-middle-class neighborhood in NJ. My mom had a well-paying public job (around $40K-$80K depending on how experienced she was). My dad worked in the private sector, and frequently in contract positions, and jobs in his field had a similar (but sometimes slightly higher) pay range. However, my dad was never much of a go-getter and can be really abrasive, so he had about 29 different jobs over a 30-year period or so, and was between jobs for almost as much as half of my childhood, if I recall correctly. So he made about half as much as he could have. Nobody else in our neighborhood had so much that our dad felt like he couldn't tell us kids we couldn't get toys or do all other sorts of things we wanted to do that cost money all the time when we were growing up. There were lots of things we didn't have, but that other families in our neighborhood had, and that we didn't get until years (sometimes many years) after other people first got them (things like a microwave oven, a cordless phone, and so on). Us kids never had TVs in each of our rooms (one or two of us eventually got little ancient black-and-white ones that had an antennae rather than cable, and that could only get about three stations, from some relative), and we weren't bought cars by our parents when we were teenagers (which seems to be common practice in a lot of middle-class families nowadays) except for my big brother (After high school, my parents bought him a very cheap, ugly, and old surplus Ford Pinto from the Post Office, which was getting rid of them. It quickly terminally broke down, and my parents didn't replace it.). So that's how much money we had in our household of four children, and that was our perspective. Other parents in the neighborhood had a lot of less-than-white collar jobs, or more unprestigious white collar jobs like my parents had. I can't remember ever knowing a kid from my elementary school whose parents were doctors or lawyers or anything like that (One dad was a cop, another was a garbage-man who became a cop after many years, at least one mom was a nurse, at least one dad was a carpenter, one dad owned a little Chinese restaurant located in a strip mall, one etc. The most preppy were a couple who were both college professors (but they were not hob-nobbing with amazing scholars or anything like that, though- their subject was library science or something like that), but they were the ones who didn't fit in with the neighborhood, and actually originally were from some place out of state.). And the bar that used to be located a few blocks from my house always had its pretty fair share of fistfights.
That may seem like a lot by way of explanation, but I just want to show where I'm coming from, in case points of view from another area of the country (but a similar demographic) just happen to be different. Now on to discussing vacation:
By the time I was a young teenager, going to Hawaii for vacation seemed like it had become a cliche: everyone wanted to go there, as far as I had ever heard. That's hardly elitist. Elitist, as far as I've ever heard, is going to places like Martha's Vineyard, to all the little vacations spots where only the rich go. In between elitist and middle class are maybe things like going abroad and going to ski resorts. People who don't have a lot of money go to Hawaii, but they only go for 1-3 days, or they go for a week at most. If you want to say Obama is elitist for not going to national parks (a little boring for a grown man with a sophisticated mind, if you ask me) I think you at least have to take into account that people tend to go to national parks instead of Hawaii when they don't want to go through the hassle of getting on a plane because they have young kids, or bear the extra expense of going on a plane because of the cost of raising kids. Obama is hardly in a position where planes are a hassle to him or money is still tight for him. The Republicans are picking on him for going after the American dream. To me, this criticism really seems to have a lot more to do with jealousy or with trying to take advantage of jealousy than it is legitimate.
The only thing you can say clearly about social class and going to Hawaii I think is that you can't be absolutely poor and go to Hawaii. You could probably just about pay for at least a few days in Hawaii by clipping coupons all year long, or getting a grocery store's club card and trying to buy things that are on sale and stock up a lot, or picking up a little second job, like a paper route or a seasonal job, for a month or two.
Despite all this, one thing I will say is that going on vacation at all is probably not the best PR for Obama, and that Americans would probably like to see their candidates fight tooth-and-nail every step of the way instead of taking a break in the middle of a campaign. Remember, the Republicans want you to see Obama as the stereotypical dumb, lazy black guy, so it makes it very hard for them to do that-- especially in light of all Bush's and McCain's partying and vacationing-- if Barack never takes a break during the whole campaign.
But if you really want to know what's elitist, it's sending a bunch of working-class and middle-class people off to die in Iraq for some bullshit reason and acting like you don't even care-- not going to Hawaii on a vacation once.