Hey Joe! Post some pics of your boat if you can. If you've not heard of it, check-out the Forum at TinBoats:
TinBoats.net • Index page
I've owned a couple Jons, and there's lots of great ideas to be had on their Forum. I've also owned a couple of the 2-man plastic pontoons. I like the smaller boats, they certainly have their place, and are an inexpensive way to get on the water.
Something I always liked was carpeting, it sure makes things lots quieter. Comfortable seating is a must, and depending on your fishing style, I'm sure you could get some ideas to add an inexpensive casting deck and seat up-front, if you had the interest.
You mentioned rowing, do you have, or have plans on a trolling motor?
I fished with a guy at Reelfoot who had a seat mounting track system I'd never seen. The seat swivel bolted to a plate that had a "lip" on the front. There was a track which attached to the front of his bench seat (like a piece of angle with a slot all down it's length in the front), and you held the seat vertical, slipped the lip into the track at any point along the track, so you could set to either side, or centered (or anywhere in between), depending on where you wanted. Was a slick idea, and I was pretty surprised I'd never seen it (but sometimes feel as if I've lived under a rock). I wished I'd have asked him where he got it. Maybe someone else here is familiar with it?