Why should you feel ackward? You stated clearly your concerns and needs, and you are looking for a job. You are entitled to take vacations or days off, and you are entitled to open yourself to other opportunities. You were willing to make yourself avail within your parameters, and of course they will want someone who can do a full run if given the option, but no reason that should put you in a lower position or at a disadvantage. Go, feel good about yourself, and enjoy the job fair. If you see this employer, say hello, make nice and some small talk, and move on.