R7000 looking for configuration guidance

> I have an internet provider WiFi router/modem [...]

   Not a very detailed description of that device.

> [...] I though this config would separate the guest phones/portables
> from my "work" Lan. [...]

   Some of us may not know which end of your house is the "work" end,
but, either way, it can be tough to isolate much with only two routers.
(And it's seldom worth the bother.)

> [...] In the past, this all seemed to work fine as I could "share"
> across the two Lans [...]

   I don't see how.  With two LAN subnets, I'd expect to need to do some
extra routing configuration to get data to move between them.
Typically, that would be done by specifying a static route on the outer
router.

> So I thought I could just turn off DHCP on the R7000, [...]

   There's more to it than that.

> I looked online to find examples of how to configure my situation with
> a single DHCP (a single network). No joy.

   "online" is a very big place, with many examples of many things.

> After attempt 1 (above) I tried [...]

   Also a bad idea.

   If you'd like to have one big LAN, with one subnet and easy sharing,
then the usual approach would be to configure the inner router (R7000)
as a wireless access point.  Astoundingly (perhaps), this is covered in
the R7000 User Manual.  (Although the pictures were better before the
latest revision.)

   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".