From: "Harry Porter" <harry.porter@verizon.net>
You can't carry room offers from an AC property to LV any more than you can
from one AC casino to another in AC. However, in either case a host can more
than likely work out an advance room comp for you at another property. We
stayed at Paris for 2 nights this last January by this means on a stay set up
by a Bally's AC host.
That's really a shame, because we've tossed dozens of 2- and 3-night offers in
AC. (Some casinos will charge your comp account $200 for the room. My wife
swears that she checked, and Bally's doesn't do this.)
The rooms here are never really a help to us, because we're 75 minutes away.
They're a help to the casinos, of course. 
> But the Park Place people said that this remaining linkup, computer
system to computer system, is still a year away.
Actually this link up was completed this fall (and it's the same one that
allows you to use your AC comps in LV). The AC and LV comp
programs were merged (in September?). Players with comps in both arenas
should see their aggregate comp balance when they pop any of their PP
Connection cards in a kiosk.
I've been told that the room comps don't transfer because they have "different
criteria" in each place. In my own circumstance, I agree -- it's like a bank
only offering favorable loan rates to people who don't really need a loan. If
we lived another hour away, which is about the distance where a room could
start to be useful, we might value the offers more highly (and also receive
fewer of them).
From: johnfiske@juno.com
<<<<As you note, comps are not valid at restaurants not owned by Park Place
properties (such as Eiffel Tower).
Can you get around this by charging the food to your room and then paying
the room charge with a kiosk comp? ( Ie. Vegas Subs at LVH ) I think you can
use your comps for any room charge even dirty movies and phone charges which
were previously not compable. Am I mistaken?
They might accomodate you, but since money actually has to leave the casino
property, it's only done as a convenience to you. This is probably like
putting a restaurant tip on your room charge. (You pay those tips off when
you leave.)