Taking an excursion is the best way to enjoy this itin. .We did it yrs ago before the new locks were in use. Saw quite alot, included aerial tram, climbed towers with great views, butterfly stop, resort stop for a drink.Return to lively shopping area..food, music, etc..
Highly rec the book "Path Between the Seas"..for historical/ engibeering perspective, photos maps of orig canal. Worth the long read!