There are two approaches you can take here.
First option: don't book that trip home just yet. Go through the interview process. If and when you get to the "and when could you start?" part of the interview, be honest. Tell them you would like a two month trip because you know you won't be able to go very often once you start working full time, but that it's not booked yet and you are open to a conversation about it. Work with them to pick a good start date that you'll both be happy with. Maybe arrange some time off without pay in the first year.
Second option: you have to go home then - for a family event, or you've already booked the tickets. As before, go through the interview process. If they ask "when can you start?" you tell them. (Back in my day, starting Labour Day was perfectly normal.) If they don't like it, they can take that into account in their decision process and you might risk the job, but so be it, this trip is important to you. If they don't ask, don't bring the subject up. If you get an offer with a start date you can't meet, write back and say you'll be out of the country until whenever and would be happy to start on [specific date.] They might, but probably won't, rescind the offer.
Thing is, new hires straight out of university are rarely so critical to the operations of the company that they can't function if they have to wait a few months for you. But bringing it up before they know you might give them an easy excuse to remove you from consideration. So decide for yourself how movable the trip is, and wait as long as you can to tell them about it.