In the 700 you need to create an access rule that allows the traffic, also make sure that the Hide NAT is enabled for this network (unless you have a gateway based NAT defined).
Now you need to add a route in the 700 for the other locations network with the routers IP as the next hop.
On the remote location you need to make sure that there is a default route to the central location, so the router in the remote location is the site's default gateway and in the link between remote and central there is also a default route pointing to the central site. Then last but not least the default from the router on the central site to the 700.
Regards, Maarten