I found one way to be sure that PPTP is the
route being used for all connections,
i.e., disable all other routes that
go from WLAN to WAN.

The route needed is "PPTP.......to......any"
However, you still need to allow PPTP _into_ the WLAN port.

it brings 2 questions....
a) not knowing the PPTP ports, I just set it to "any"....
How dangerous is this?  I mean, if there are no sockets
listening on any ports, is it a problem to let the traffic in?

Of course, opening only the minimum is preferable.

b) When I did the above, i.e., disabled WLAN->WAN traffic,
internet only worked with the PPTP up.  However, that
does not *prove* that WLAN->WAN would not use the direct route ever.

Anyone have leads on that question?  Sorry, it's off-topic,
it's probably strictly a Win/PPTP question.

Although, I have the same question on IPSec.
I just haven't tried IPSec yet.

Thanks
Seth