You can just plug both into the LAN and your PCs will pick the best
path for each packet. I was sharing internet connections with my
Comcast neighbor until he died. His machine would get out on my DSL
when Comcast was down. I got his extra speed when it was up.
Century Link only gets me 10mb here but it is solid as a rock. Comcast
is real fast when it works but it is down a lot.