The seats in the '97 Ultra we had were just fine on road trips, although looking at them you wouldn't think so.
I start feeling the drive in my current PA after about 45 min.
Try them before you ditch them? Also it may be a good idea to have Craigslist searches going, because it seems like the nice ones for cheap would be picked up quick by flippers.
Also spread word around that you are looking for one, because they are cars typically purchased by older individuals, and when they are no longer able to take care of themselves, the car may get absorbed by the family as an extra car. Some take the opportunity to shed the extra car, especially if the have money pounding at their door, instead of hassling with listing the car.