DSL-N :: Please Help Wireless.

Debian Etch.
A landlord wants me to setup wireless in a large building, I will be employing bigger antennae, and Repeaters.

I want to setup building before buying landline connection, method:

I bring internet to box_1 by GPRS cellphone,
modprobe cdc-acm
/usr/sbin/pppd connect '/usr/sbin/chat -v "" "AT&F" OK "AT+CGDCONT=1,\"IP\",\"LEMONINTERNET\"" OK "ATDT*99#"' noauth /dev/ttyACM0 921600 defaultroute noipdefault user ppp usepeerdns

Box_1, I want to "pipe" ppp0 to wlan0. wlan0 to Box_2, Ad-Hoc?. Box_2, notebook/laptop has wireless card, I will roam building.

I need to NAT, is this correct?
modprobe iptable_nat
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -A FORWARD -i ppp0 -o wlan0 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE

Run pppd
tail -f /var/log/messages
local  IP address
remote IP address
primary   DNS address
secondary DNS address

ppp0     Link encap:Point-to-Point Protocol
        inet addr:  P-t-P:  Mask:

pppd is always Mask:

I am reading wireless HOWTO etc., I WANT TO DO MANUALLY.
Can I do this?

route add default gw
route add dev ppp0

route add dev wlan0

Any input many thanks, Andrew.
Best Regards.

I'm afraid I'm not enjoying networking at the minute.
Because unfortunately I don't quite understand exactly what I am doing, perhaps the best I can do is systematically try options.
I hope somebody could offer some input and perhaps I will learn and understand.

Cellphone won't function as a modem without pppd options defaultroute noipdefault usepeerdns.
Usepeerdns creates an /etc/ppp/resolv.conf file containing two nameserver lines with the addresses supplied by the peer.

Do I need to add a line to /etc/ppp/resolv.conf ?

Perhaps I should be using dhcpd & dnsmasq or something ?

I am trying to gain some understanding.

Any input appreciated.

original here.