I've discovered that you can actually sell balloons, and in fact give them away. The only issue worth noting, is that unlike Rollercoast Tycoon and similar, the price of a balloon actually adds up. You have a park entrance fee, and then you can set the fee per item, like $10 to get on the pedestal-built-into-a-fence, or $50 to ride the jeeps. Or, $20 for a hotdog or $60 for a giant stuffed T-Rex. The price of a balloon will suffer the park, BUT the price of admission will cover the balloon costs. Also unlike RCT, there is no monthly cost for concessions. They only change money when a customer arrives, they have no monthly fee.
Also, gameplan: Get a lot of excavators. Selling fossils is a fantastic way to get money. You could set the admission fee and per-item fee very low and just sustain on fossils. Well, mainly sustain on amber and gems. Every time I extract from Amber, it turns out to be already 100% and wasted. Even sending your team to waste time at an "exhausted" dig will yield items for profit.
And on that note, I'd have to suggest working on the Hell River A and B, and the start location B. In those, you can find the T-Rex, the T-Rex's preferred prey, and the T-Rex's preferred prey's preferred friend, giving you a trilogy of dinosaurs that synergize with each other nicely and boost the attractiveness, being that they're all from the same era and territory, and they've got special relations to each other. This gives you nice herbivore interaction for the elven funlovers, and carnivore circle-of-life for the goblin thrillseekers.
I wonder though, can a herbivore kill a carnivore? I've not witnessed it...