I've done similar things to what RLS7201 did..
I have a WRT54GS for local WiFi which has it's WAN port connected to a Picostation M2HP which I use to connect to the campground.
So, the WRT54GS is setup like a home access point, clients connect to it and it's WAN port is the Internet (Picostation). I used some 172.16.x.x IP addresses so as not to conflict with a campground that used 192.168.x.x. But you could easily use 10.x.x.x.
When I get to a campground, I pull out my "kit" and plug in the power adapters and put an antenna on the Picostation. I then take my tablet and connect to the LAN side of the Picostation and login to the web interface and then I select a wireless AP on the campground to connect to based on signal strength and apply the settings. Then it works.. :)
I stayed away from the wireless repeaters because for the most part all they do is slow things down and clog the airwaves.
There was a question about IPs. Here is my setup:
WRT54GS - LAN - 172.16.56.1
........- WAN - 172.16.57.2, Gateway 172.16.57.1
Picostation - LAN - 172.16.57.1
............- WAN - DHCP (I get an IP from the campground)
The Picostation is configured as a wireless client otherwise known as WISP (Wireless Internet Service Provider) client with the Router and Firewall enabled. The WRT54GS is configured as a normal Access Point (AP).
My setup cost me $75 for the Picostation, $10 for a 9dbi omnidirectional antenna and I had the WRT54GS left over, but you could get a wireless router for about $30. I've run Tomato on the WRT54GS till recently cause I had some weird problems, so I'm going back to DD-WRT and see what happens. So far very happy with the Picostation.
- Ken