What do you think about just using scramble portal or possibly portal to portal redirect to mess with their access point instead of just rushing toward the control station? It seems like getting in range to tag it and then turning around to shut it down would work better to me.
If we make it out alive we should definitely start carrying around a small strike force of undead in Viserys' cloak or something. This would be easier if we could bust out like 25 or so expendable shock troops.
Hell, I'd take as many as we can carry around without making it hard to carry loot. Maybe we could get some of our old bags out, fill them with unliving servitors, and have Viserys carry them around on his belt?
Edit: actually, could we use PtPR to open the portal directly into that earth portal in Westeros, then pull in part of our garrison we wouldn't mind losing to even the odds a little for the attack? My original thought was to put the other end somewhere harmless, but we might as well take advantage of it if we can.