Giant Boulder 500

Just got this bike and wonder what to do with it :) First thought is a vintage drop bar conversion with RSX levers, 3x7 or 3x8, maybe I wider flat bar? Those dia compe SS8 levera feel great. Tire clearance is plentiful, currently running 26x1.95 and there's much space left. What do you think max width could be? Size 19.5, feels a bit too small for me being 180cm tall, but I can live with that.

What do you think?