you can avoid overstay if you want (Seniors correct me if I'm wrong) ... if PPR is the only thing you're waiting for and if you don't get an interview call from Buffalo (fingers crossed) ... you can do one of the following two:
- go back to your home country without overstay (report Buffalo of your new address) ... when you get PPR by email, ask Buffalo to have PPR routed to home country VO (I read this on this forum somewhere, you'll have to search) ... Buffalo will ask for PP copies and after that your home VO will issue you a new PPR ... you send your PP to home country VO and get it stamped from there
- go back to your home country without overstay, apply for visit to Canada (or apply while you're in US and get it within 30 days) ... when you get PPR ... go to Canada and send PP to Buffalo just like other Inland applicants do ... leave Canada as a visitor and re-enter to land
now all this assumes Buffalo doesn't call you for an interview ... but to be on the safest side, go back to home country and apply for US visit visa as well ...
P.S.: Can an interview also be re-routed to VO in another country?