Nighthawk X6S AC3600 model R7960P need to connect to older cable modem router with IP ad 192.168.0.1

> I do not want to change the IP address to the 192.168.1.1 range since
> there are quite a few wired devices with static IP addresses and I don't
> want to go to the trouble of changing all of those. [...]

   When you say "static", do you mean _really_ static, that is,
configured on the device itself, or only reserved (dynamic), that is,
configured on the (DHCP server on the) router (C6300BD, router section)?
(Either way should give similarly reliable/fixed addresses, but it's
nice to know what's actually happening.  Using static addresses requires
more care in the configuration of the DHCP server.)

> I am not quite sure how to go about this. I believe the problem will
> be the 192.168.0.1 gateway address...

   Fear not.  Configuring an R7960P (or most any other router) as a
wireless access point will make it too stupid to cause this kind of
trouble.  Visit http://netgear.com/support , put in your model number,
and look for Documentation.  Get the User Manual.  Read.  Look for "Set
Up the Router as a WiFi Access Point".

   With the default option, "Get dynamically from existing router", your
R7960P-as-WAP will get its (LAN) IP address from your main router
(C6300BD), just like your other DHCP clients.  And that means that it
will have an address in the "192.168.0.*" subnet (just like the other
devices on your LAN).  (And if you chose the other option, then _you_
would need to configure the R7960P-as-WAP with a (static, LAN) IP
address in that same subnet.)

   The R7960P-as-WAP will also be too stupid to act as (or care about)
any gateway, or DHCP server, or much else; all those tasks will be
handled by your main router (C6300BD).

   A wireless access point is all-LAN, and uses the same IP subnet as
everything else on your existing LAN.   It should be mostly harmless.
What could go wrong?  (Only one way to find out.)