I'd go for park. As you say, the national park lot gets fewer visitors.
And since you'd probably want children to visit the lot as well, park is pretty much the only option, unless you're willing to go for library, but that doesn't seem suitable (as far as a know, children from unplayed/non-active households don't normally spawn on other types of lots). Unless you use Get Together and use the club system - in that case you could essentially pick any lot type.
As for lot traits, I'd definitly go for convivial, since it's intended for group outings and party place might be a good one too, although you can't host goaled events on holidays. Sunny aspect is one I often use for parks, but great soil would also be a good one since you want harvestables on you lot.
