I built my switch rod from a Batson 7 wt. 10'-8" 4 piece blank. I love that rod and use it about 50% of the time. If I could only own one rod, it would be a 7 wt switch rod.
I have never fished the park, but I frequently fish tailwaters and medium to large rivers. The right line, leader and fly/streamer combination is critical for a good fishing experience. With the right combination you can turn over a streamer the size a small squirrel or mend a nymph 40 feet out.
I use an #8 WF floating line or a skagit with a sinking tip. I'm still experimenting with the skagit line weights to find the right combination.