Yes. It is ideal for the angler. You can carry your own light gear or rent it at some of the Resorts en route.
Drop-in to any sport shop in New Zealand to suss the local fishing rules & pickup a fishing licence.
Can I buy food on the Track?
Yes. You do not need to bring any food with you though costs for food will be higher than in Picton.
Parking at the Trailhead?
In Picton there is secure parking at the boat terminal.
Your valuables should be safe in your vehicles though if you are staying in a Hotel or B&B you may be able to make arrangements to store valuables there.
Are there toilets on the Charlotte?
The Resorts have indoor toilets and hot water. Campsites have outhouse-style loos.
Trampers still need to carry toilet paper, a lighter, and alcohol gel to disinfect if they happen to get the urge to purge somewhere between toilets.

Campsite outhouse.
Accept that you might find yourself shitting in the woods at some point on the Track.
Where are the nearest showers?
Tenters may be days without a shower, splashing in cold creeks to clean-up. All the resort accommodations have hot showers, however.
The ferry terminal in Picton offers a laundrette and public showers.