I didn’t know about the N11’s weight limits.However,a route which I have used by car but is still mostly dual carriageway after the first bit is to drive into Figueres and pick up signs to Ripoll(via Olot) then south to Vic,Manresa to pick up the N11 at Cervera then toll free to Lleida.After that to Zaragoza the national and motorway run parallel which I haven’t used in 20+ years since I currently continue south towards the coast in my car although it is single carriageway and good for trucks.