connecting a remote client router to a home VPN server(router)

Still trying to find my way around VPN's but I have a question. I would like to set up a client router at my parents house (in another country) to link via VPN to my home Network-that has a netgear R7000 router with open VPN enabled. My R7000 allows me to log in to my home network (using my laptop) but I would like to set my parents house up so they can use a Apple TV through a client router to my home network to get around the location issues. I have a spare Linksys e1000 that i can flash to DD-wrt but i don't know what to do from there to get it linking into my home VPN Server/Router. any help would be great thanks