...I'd need to forget about targeting one species of fish.
I like fishing, but there are way too many negatives that would go along with being a guide.
I wouldn't consider guiding professionally, but if I wanted to make a living at fishing, then what I'd do is:
I'd aim to become familiar with a few bodies of water. Ideally those bodies of water would be close to each other and not too far from a population center (city).
I like many aspects of Madison, WI, and its few lakes would be a good place to be. Lakes Wingra and Waubesa have lots of muskies, Mendota has lots of bass, and Monona has all sorts of fish.
Rather than target one species, which I'd prefer, I'd figure to try and cover those very few lakes. Knowing how to catch each of the species that inhabit a lake would mean that I would not need to look only for clients that want to catch my preferred species. Because of this I could increase my potential client pool to include anyone who wants to fish nearby.
Learning how each species is caught at each stage of the year would also increase my knowledge of fishing for my preferred species.
Rather than use a standard fishing boat, as in an aluminum or fiberglass v-hull, I would think that a modified pontoon boat would be quite a good idea.
Pontoon boats are primarily used by people who drive around a like while sitting down and entertaining friends.
If all of the sides and seats were removed, the pontoon boat would merely be a large floating platform. And a big floating platform would be excellent for fishing off of. Rod holders could decorate the back for when trolling is the way to go. The console (steering wheel holder) could remain just ahead of the rod holders. A big compartment could be sunk between the pontoons for carrying all of the different tackle for each fish species...
Being a fishing guide is not an appealing job. But by using a highly modified pontoon boat and sticking to a small number of local lakes would mean that I could probably get lots of different people to hire me for a day, rather than need to look only for serious fishermen, who likely have their own boat anyway.
(Modifying the boat would be fun too.)