To answer your questions...
No you can't transfer items onto your Neopets account. All items in Petpet Park are unique to Petpet Park and don't exist in Neopets. However, Neocash in Petpet Park is also usable in Neopets.
And the game itself has improved a lot over time. It's a lot less buggy than it used to be. But I admit it's still buggy and you still need a pretty good computer and fast internet to really be able to play it well.
As for things to do...
There isn't a ton of things to do right now, but I still manage to play it four or five hours a day.
There's jobs you can do (which are really fun and usually give you a wearable item!)
There's games, which in my opinion, are much much more fun and adorable then the Neopets games.
You can also fish, pick berries, and pop popcorn.
But if you use a guide, you can do all the jobs in about two hours. And the only thing to buy with the park points you get from games and jobs is clothes for your petpet and food.
In the future, you'll have to keep your petpet fed to be happy. But currently that function hasn't been implimented yet. So right now on my petpet I have about 983475983746 food items I don't really need.
But it's really fun if you're the type of person that likes dressing up your pets in Neopets and making them cute! Because in Petpet Park there are TONS of really cute clothes to dress your pet up with.
Currently my petpet is a vampire zombie oukin.
You can have an interactive chat with other petpets in the park. But the words you can use are VERY limited. (Can't even say numbers)
And right now most players are extreme nubs that don't even bother getting to know the game and dressing up their pet. Also, most of the players of petpet park are in like.. third grade.
My character has been asked to be some nubs boyfriend about 98347658937 times. So it gets annoying talking to all the kids sometimes.
But it really is a ton of fun! And the thing is.. one day this game will be really awesome and have tons more to do. But if you play it now and get all the goodies they have, in the future you'll be one of those people with tons of really rare items because no one but you bothered to play it "back then". Kind of like Neopets now.
Anyways, if there was a section, I dunno, I could like be the information person or something. I dunno. But I think there should be a section.
Hope this all wasn't tl;dr.
