Nahuel Huapi National Park was founded in 1934 and is entered through more than one entry portal, so it pays to decide in advance which part of the park your day is about.
Boat excursions on the lakes reach Isla Victoria, which has a restaurant and public toilets, and Puerto Blest, which has restaurants. Departure times change between summer and winter, and the time you get on the island can change with them. In high season, booking is recommended for the Puerto Blest excursion to be sure of a place.
The trade-off is the cost of a lake day: on top of park entry you pay a boarding fee at Puerto Pañuelo and the boat fare itself.
Pets are not allowed in the park. Assistance dogs for visitors with disabilities can enter with a permit, requested in advance by email to the park’s accessibility office.