I too am talking about sitting in my home, want to access the internet, with a masked IP, using VPN on the router.
This is so frustrating though. I just put in an order for the ASUS AC68U but I think I will give it back. Looking at the manual, there are no VPN Client options (like Isee on the N66U). There are only VPN server options, which appear to be the opposite of what I want.
The N66U runs essentially the same firmware as the AC68U so there should be little difference in VPN capabilities and setup. (I don't see a VPN client on the N66U either.) The AC68U is basically the same router with faster CPU and AC capabilities added to the RF section.
To do what you want, it's most likely that DD-WRT or another third party firmware will be required. Except to get a VPN client or some other specific feature, not sure if I would run DD-WRT on an AC68U. Apart from some extra features in DD-WRT, the stock firmware is probably more stable and the Merlin builds a little better yet. DD-WRT tends to be a little more stable on older hardware. From what I've read 5GHz WiFi does not always work well on DD-WRT.
It would appear that ASUS Merlin does what I need .
Also per their web site, its interesting to note that do say that "While Asus has now integrated the OpenVPN server and client support into the official firmware, the Asuswrt-Merlin implementation retains some additional flexibility, such as the ability to configure two separate server or client instances."
For an ASUS router, I am more comfortable with Merlin (over dd-wrt) as somehow its ASUS sanctioned. Also more brick-proof, so they say. On the Netgear R7000 Nighthawk, I would only use dd-wrt and only if I needed the functionality.
So the my latest plan is:
Disconnect, and park for safe keeping, the Netgear R7000 (now my main router). Don't want to touch yet in case I need to roll back to it.
Connect the ASUS AC68U and upgrade from factory to ASUS Merlin firmware
Configure it as a main router, radios off, static IPs, static routing, OpenVPN Client, etc
Once proven and working, redeploy the Netgear as an AP. No need yet to flash it to dd-wrt just yet.
Lots of diversity here with the two different routers each with their own stock and own third party firmware.