Good morning Woody, the best sized outfit that I have found is an 8-1/2 ft. 4 wt. rod and the Triangle Taper weight forward line is fine, as well as SA mastery Fast Taper line. I usually use just a little bit more leader when I'm nymphing but that will depend on the length of the rod that you are using. There is a lot of latitude in this area and many other sizes will work fine. If you go over a 5wt. it may be overkill in the Park. 3wts. are fine but they may limit you a litttle on bigger water. They also cause a few problems with mending on larger water. Overall, I'd say your about in the middle of the spectrum. The biggest factor is being correct with your casting and mending skills. Be sure that you have those down pat and practice them in the yard or somewhere in the open every chance you get. Good fishing to you this Spring.
Hugh Hartsell---East Tn.