Thanks for the reply Steve. That's what I was thinking, that there probably isn't any risk of anything breaking out of the tunnel between the ISP and the WAN connection on the pfsense box, but I wasn't sure.
Thanks for the link as well. I should have mentioned that I'd seen it, but it seemed easier to plug a cable between the modem and one of the switches on the LAN as no other changes were necessary. I haven't made any changes for NAT on either the modem or the pfsense box, although may have turned it off on the modem a few years ago when I put it in bridge mode as it's turned off now. I assume the modem is just passing the internet connection to pfsense and not doing any NAT and that pfsense is the only thing doing NAT.
The reason I was thinking of using the modem for wireless is to segregate my Directv network from the LAN by creating a VLAN. The Directv boxes are networked using coax, but they need to use wireless to get an internet connection without some other piece of hardware I don't have and would have to buy. I don't like having boxes I don't control on the LAN but the WNDR WAP doesn't do VLAN's. I could buy another access point, but since the modem's wireless isn't being used I figured why not, assuming I'm not opening up a security hole. Since it's already working most of the configuration is already sorted out.
Bill