I did "the drive" twice in my search for a float job. Once in early March: "come back in a month or two in the middle of April, we'll have a better idea then.." and then once again in the middle of April: "shoot, ya shoulda been here in the middle of March, that's when we did our hiring."
What's a guy to do? At then end of it all, I managed to get a job in my hometown which garnered me enough time to get a dock/185 gig over the phone.
Now, that was back in 1997, so things may have changed a little, but I still think that it is a worthwhile trip - if you can afford it... At the very least, you'll get to drive across the country and see places that you'd never otherwise go. Also, you'll get an idea of where you do and don't want to live. You might show up in Pickle Lake, and think, 'ahh, paradise', OTOH, maybe not - no Starbucks, so elsewhere.
You'll also get a feel for the places that you might want to work. I happened to visit Jackson Air in Flin Flon, MB. Bill was a great guy, took some time to talk (interview, if you will) cup of coffee, bit of a tour etc.. I went away hoping that he'd call me, as he seemed like a good guy, the hangar was clean, and well-lit, and from what I could see of the Beaver he was servicing, it was in good shape. Other, nameless, places that I've been to really gave me a bad feeling - dirty, greasy floors, engineers wearing t-shirts with yesterday's lunch and last week's oil change smeared on the front, tools and sh1t everywhere - you get the picture.
Kevinsky has some good points, too.. don't just scoot out the door unless it's obvious that you are not welcome to stay. Try and adjust your dress to suit the operation - just as a suit isn't really expected at Joe's Flying Truck Service, neither are jeans and workboots acceptable at Jane's Corporate Charters..
Whenever I've worked at a place, I've always tried to be helpful to newbys/wannabes who show up at the door. I'll give a guy a couch and meal for the night if s/he's otherwise going to stay in a hotel etc.. For several reasons - paying it forward is one; who knows, I may end up asking them for a favour some day; common decency; if we are looking to hire a new guy, and s/he happened to be a d!ck, then I'd like to be able to say that to the boss, and have my 2 cents worth noted..OTOH, if wannabe made a good impression, I'd say that too - networking without you even knowing about it! I'm not saying to show up and be a brown-noser by buying dinner and then drinks all night, but if the guys go out for coffee while you are there, spring for the round.
As to the last...I'm sure that there are ramp jobs still to be had in places - making the jump from 7 hours and a ramp to a flying seat, perhaps not this year. Still, if it was easy, everyone would be doing it.