I've got status on Northwest, and live in detroit. In winter, flights to popular, warm tourist destinations are hard---Orlando in February is nearly impossible, but we have gotten tickets for our family of four to Santa Ana on miles for a February week at
Disneyland at the 330-day mark. Within a few weeks, though, they were gone. So, if you are traveling a popular vacation route in a popular season, be prepared to plan ahead.
In lower-demand seasons, or to "not-so-touristy" destinations, it's not as hard---I just booked a long weekend in September for two of us on miles from DTW to MCO, direct on the way down, connecting back, geting the dates and times we wanted. Last month I booked a pair of tickets just two weeks in advance for a long weekend to Charlotte so that my daughter and I could start our summer amusement park season a month early at Paramount's Carowinds, and there were plenty of award seats available.
(On NW, you can use double miles to get around capacity limits, but I only do that in emergencies---it significantly reduces the value of your miles.)
In my experience, unless you are already flying a significant amount, and can consolidate your flights on a single airline, it will take quite a while to build up enough rewards to get tickets---most cards give 1 mile per dollar for most transactions, and you typically need at least 25K miles for a single ticket. It took my wife five years to rack up enough miles for a round trip flight on her FF account, and she takes 1-2 leisure flights per year that we pay for. (It would have taken longer, but we went to Geneva last year on a paid ticket, and that's nearly 9,000 miles right there.)
Furthermore, if you are mostly using award tickets to fly domestic coach routes, the value of your miles can range from less than $0.01 per mile to at most $0.02, but usually on the lower end of the range.
Bottom line? If you aren't a frequent flyer already, it's probably a better bet to go with a card that gives a cash payout instead, and set that money aside in a "vacation fund."