We also took the tunnel and had no problem ! The 15 kilometers from Vik to there were quite hard though with a full loaded touring bike, but the area is so beautiful !
We came across this old way in hopes of avoiding the tunnel, this “road” (once would have been the main way) was great fun to ride (don’t try on skinny tyres!) but toward the end there is a landslide area which may be passable pushing a light bike with very steady footing, but with a loaded touring bike could be an easy death. The 1044m tunnel was easy, not the best road condition but no cars when we went through and we didn’t slide down any cliffs :)