The Linksys processor is a 200MHz MIPS32 core which has a memory management unit with simple fixed mapping translation (FMT) - see this link for more details - so FreeBSD may be possible!
description of MIPS32 core
Reminder of other details:
RAM: 2 x IC42S16400, 64Mbit (4M X 16) RAM chips (16MB)
Flash: Intel TE28F320 C3 flash 32Mbit chip (4MB)
CPU: Broadcom [WWW]BCM4712KPB, running at 200MHz
Ethernet: [WWW]ADMtek ADM6996 5 port 10/100 switch
Wireless: On board; Broadcom BCM2050KWL