Schools start sending out invites for interviews as early as late July. If you have access to your email abroad and can schedule possible interviews, you will be fine. I would plan to be back by late July if not. You will need to be around in early June to submit your application, get the necessary paperwork in, etc. and that process takes a couple weeks, then you will be getting emails, possibly, from schools for secondary applications that will need to be sent off, usually within a short timeframe, before they extend interview invites. It's not the best summer to take off overseas.