I have a rather unique situation. I just bought a boat and am now living aboard full time. Back in my apartment, I had a WRT54G wireless router that I plugged into my cable modem, such that it provided Internet access via both wired and wireless.
I want the same setup on my boat, except the Internet connection is going to come from the marina's Wi-Fi network. I'd like to keep my own wireless network rather than just pointing my wireless devices at the marina's Wi-Fi for two reasons: 1) as I sail around, different marinas will has different wireless network names/passwords and I don't want to have to update all my devices, and 2) I want to be able to transfer files between my desktop and laptop while at sea, where there is no Internet access.
I would also, if possible, like to avoid buying any new hardware. Can I accomplish what I want using only my WRT54G rounter, perhaps by flashing it with DD-WRT? I have a 2 MB memory model, so I can't use the full-capability DD-WRT. If it can't be done with only this device, do you know of a simple access point that I could buy which I could plug into the WRT54G's WAN port and have it behave just like it was plugged into the cable modem back in my apartment? This hypothetical access point would need to be easily configurable to bridge to various Wi-Fi networks. If this access point had features such as removable/remote antenna (for mounting up on the mast) and extra long range, those would be plusses.